Current understanding of auditory neuropathy.

PubMed

Boo, Nem-Yun

2008-12-01

Auditory neuropathy is defined by the presence of normal evoked otoacoustic emissions (OAE) and absent or abnormal auditory brainstem responses (ABR). The sites of lesion could be at the cochlear inner hair cells, spiral ganglion cells of the cochlea, synapse between the inner hair cells and auditory nerve, or the auditory nerve itself. Genetic, infectious or neonatal/perinatal insults are the 3 most commonly identified underlying causes. Children usually present with delay in speech and language development while adult patients present with hearing loss and disproportionately poor speech discrimination for the degree of hearing loss. Although cochlear implant is the treatment of choice, current evidence show that it benefits only those patients with endocochlear lesions, but not those with cochlear nerve deficiency or central nervous system disorders. As auditory neuropathy is a disorder with potential long-term impact on a child's development, early hearing screen using both OAE and ABR should be carried out on all newborns and infants to allow early detection and intervention.

Amino-oxyacetic acid as a palliative in tinnitus.

PubMed

Reed, H T; Meltzer, J; Crews, P; Norris, C H; Quine, D B; Guth, P S

1985-12-01

Amino-oxyacetic acid, previously shown to cause a reversible loss of hearing sensitivity and a reduction in endocochlear potential, was tried as a palliative in human tinnitus. Because the drug seemed to have a cochlear site of action, patients were selected for the study if their audiograms were indicative of cochlear lesions and if there was a reduction in tinnitus following intravenous lidocaine (lidocaine positive). Ten such patients received either 50 or 75 mg of amino-oxyacetic acid four times a day orally for one week or placebo administered in a random, crossover, double-blind design. Of these ten, three reported subjective lessening of tinnitus. One of those three and two others not reporting subjective lessening of tinnitus showed a substantial improvement in speech discrimination scores while receiving amino-oxyacetic acid but not placebo. One additional patient who did not receive lidocaine also reported a subjective lessening of tinnitus. Four patients who were lidocaine negative showed neither subjective nor objective improvement in tinnitus after treatment with amino-oxyacetic acid.

Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.

PubMed

Kitano, I; Mori, N; Matsunaga, T

1995-03-01

To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.

Energy extraction from the biologic battery in the inner ear.

PubMed

Mercier, Patrick P; Lysaght, Andrew C; Bandyopadhyay, Saurav; Chandrakasan, Anantha P; Stankovic, Konstantina M

2012-12-01

Endocochlear potential (EP) is a battery-like electrochemical gradient found in and actively maintained by the inner ear. Here we demonstrate that the mammalian EP can be used as a power source for electronic devices. We achieved this by designing an anatomically sized, ultra-low quiescent-power energy harvester chip integrated with a wireless sensor capable of monitoring the EP itself. Although other forms of in vivo energy harvesting have been described in lower organisms, and thermoelectric, piezoelectric and biofuel devices are promising for mammalian applications, there have been few, if any, in vivo demonstrations in the vicinity of the ear, eye and brain. In this work, the chip extracted a minimum of 1.12 nW from the EP of a guinea pig for up to 5 h, enabling a 2.4 GHz radio to transmit measurement of the EP every 40-360 s. With future optimization of electrode design, we envision using the biologic battery in the inner ear to power chemical and molecular sensors, or drug-delivery actuators for diagnosis and therapy of hearing loss and other disorders.

Hearing dysfunction in heterozygous Mitf(Mi-wh) /+ mice, a model for Waardenburg syndrome type 2 and Tietz syndrome.

PubMed

Ni, Christina; Zhang, Deming; Beyer, Lisa A; Halsey, Karin E; Fukui, Hideto; Raphael, Yehoash; Dolan, David F; Hornyak, Thomas J

2013-01-01

The human deafness-pigmentation syndromes, Waardenburg syndrome (WS) type 2a, and Tietz syndrome are characterized by profound deafness but only partial cutaneous pigmentary abnormalities. Both syndromes are caused by mutations in MITF. To illuminate differences between cutaneous and otic melanocytes in these syndromes, their development and survival in heterozygous Microphthalmia-White (Mitf(Mi-wh) /+) mice were studied and hearing function of these mice characterized. Mitf(Mi-wh) /+ mice have a profound hearing deficit, characterized by elevated auditory brainstem response thresholds, reduced distortion product otoacoustic emissions, absent endocochlear potential, loss of outer hair cells, and stria vascularis abnormalities. Mitf(Mi-wh) /+ embryos have fewer melanoblasts during embryonic development than their wild-type littermates. Although cochlear melanocytes are present at birth, they disappear from the Mitf(Mi-wh) /+ cochlea between P1 and P7. These findings may provide insight into the mechanism of melanocyte and hearing loss in human deafness-pigmentation syndromes such as WS and Tietz syndrome and illustrate differences between otic and follicular melanocytes. © 2012 John Wiley & Sons A/S.

Displacements of the organ of Corti by gel injections into the cochlear apex

PubMed Central

Salt, Alec N.; Brown, Daniel J.; Hartsock, Jared J.; Plontke, Stefan K.

2009-01-01

In order to transduce sounds efficiently, the stereocilia of hair cells in the organ of Corti must be positioned optimally. Mechanical displacements, such as pressure differentials across the organ caused by endolymphatic hydrops, may impair sensitivity. Studying this phenomenon has been limited by the technical difficulty of inducing sustained displacements of stereocilia in vivo. We have found that small injections (0.5 to 2 μL) of Healon gel into the cochlear apex of guinea pigs produced sustained changes of endocochlear potential (EP), summating potential (SP) and transducer operating point (OP) in a manner consistent with a mechanically-induced position change of the organ of Corti in the basal turn. Induced changes immediately recovered when injection ceased. In addition, effects of low-frequency bias tones on EP, SP and OP were enhanced during the injection of gel and remained hypersensitive after injection ceased. This is thought to result from the viscous gel mechanically limiting pressure shunting through the helicotrema. Cochlear microphonics measured as frequency was varied showed enhancement below 100 Hz but most notably in the sub-auditory range. Sensitivity to low-frequency biasing was also enhanced in animals with surgically-induced endolymphatic hydrops, suggesting that obstruction of the perilymphatic space by hydrops could contribute to the pathophysiology of this condition. PMID:19217935

A 1.1nW Energy Harvesting System with 544pW Quiescent Power for Next Generation Implants

PubMed Central

Mercier, Patrick P.; Lysaght, Andrew C.; Stankovic, Konstantina M.; Chandrakasan, Anantha P.

2015-01-01

This paper presents a nW power management unit (PMU) for an autonomous wireless sensor that sustains itself by harvesting energy from the endocochlear potential (EP), the 70–100 mV electrochemical bio-potential inside the mammalian ear. Due to the anatomical constraints inside the inner ear, the total extractable power from the EP is limited to 1.1–6.25 nW. A nW boost converter is used to increase the input voltage (30–55 mV) to a higher voltage (0.8 to 1.1 V) usable by CMOS circuits in the sensor. A pW Charge Pump circuit is used to minimize the leakage in the boost converter. Further, ultra-low-power control circuits consisting of digital implementations of input impedance adjustment circuits and Zero Current Switching circuits along with Timer and Reference circuits keep the quiescent power of the PMU down to 544 pW. The designed boost converter achieves a peak power conversion efficiency of 56%. The PMU can sustain itself and a duty-cyled ultra-low power load while extracting power from the EP of a live guinea pig. The PMU circuits have been implemented on a 0.18µm CMOS process. PMID:25983340

A 1.1nW Energy Harvesting System with 544pW Quiescent Power for Next Generation Implants.

PubMed

Bandyopadhyay, Saurav; Mercier, Patrick P; Lysaght, Andrew C; Stankovic, Konstantina M; Chandrakasan, Anantha P

2014-12-01

This paper presents a nW power management unit (PMU) for an autonomous wireless sensor that sustains itself by harvesting energy from the endocochlear potential (EP), the 70-100 mV electrochemical bio-potential inside the mammalian ear. Due to the anatomical constraints inside the inner ear, the total extractable power from the EP is limited to 1.1-6.25 nW. A nW boost converter is used to increase the input voltage (30-55 mV) to a higher voltage (0.8 to 1.1 V) usable by CMOS circuits in the sensor. A pW Charge Pump circuit is used to minimize the leakage in the boost converter. Further, ultra-low-power control circuits consisting of digital implementations of input impedance adjustment circuits and Zero Current Switching circuits along with Timer and Reference circuits keep the quiescent power of the PMU down to 544 pW. The designed boost converter achieves a peak power conversion efficiency of 56%. The PMU can sustain itself and a duty-cyled ultra-low power load while extracting power from the EP of a live guinea pig. The PMU circuits have been implemented on a 0.18µm CMOS process.

Inner ear injury caused by air intrusion to the scala vestibuli of the cochlea.

PubMed

Kobayashi, T; Sakurada, T; Ohyama, K; Takasaka, M

1993-11-01

In a previous communication, we demonstrated that the introduction of air into the scala tympani of the cochlea causes a decrease of cochlear potentials; however, the change in endocochlear dc potential (EP) was mild and the decreased cochlear microphonics (CM) and compound action potentials (CAP) were, at least partially, reversible. In contrast, we have now found that air perfusion (3-60 microliters/min) in the scala vestibuli decreased cochlear potentials more drastically than that in the scala tympani. The change in the EP after air perfusion in the scala vestibuli was characterized by a decrease of the negative EP in response to anoxia. The CM drastically decreased upon the initiation of air perfusion and no recovery was observed after refilling of the perilymph. Histological examination showed collapse of Reissner's membrane in 12 out of 17 cochleas examined. The extent and frequency of the collapse increased with an increase in the amount of air perfused in the scala vestibuli. As the minimal amount of air needed to cause inner ear damage by air perfusion in the scala vestibuli is as small as 3 microliters, it is possible that the prognosis is worse in cases with fistula of the oval window compared to that of the round window area, if the pneumolabyrinth is involved in the pathophysiology of perilymphatic fistula. It is also indicated that air inflation of the middle ear is dangerous in cases with fistula in the oval window.

Differential physiologic effects of perfusion of scala tympani versus scala vestibuli in the ischemic cochlea.

PubMed

Kobayashi, T; Rokugo, M; Takasaka, T; Thalmann, R

1993-07-01

The effectiveness of perilymphatic perfusion with oxygenated artificial media upon the endocochlear potential (EP) was measured during systemic ischemia in the guinea pig. Differences in the effects of perfusion of the two perilymphatic scalae were determined. Perfusion of scala vestibuli with oxygenated artificial perilymph at a high flow rate resulted in complete recovery of the EP to the pre-ischemic level, whereas perfusion of scala tympani with the same medium was unable to effect complete recovery. The recovery obtained by perfusion of scala tympani was about half that obtained of scala vestibuli. The pO2 in scala media was measured during perfusion by means of oxygen-sensitive microelectrodes. perfusion of scala vestibuli led to an approximately two-fold higher pO2 in scala media than perfusion of scala tympani. During perfusion, the pO2 in scala media varied dependent upon depth of electrode insertion, with a gradient decreasing toward the stria vascularis, a direction opposite to that seen under normal metabolic conditions. These findings suggest that, in the ischemic cochlea, oxygen enters scala media more easily from scala vestibuli across Reissner's membrane than from scala tympani via the basilar membrane/organ of Corti complex.

Energy extraction from the biologic battery in the inner ear

PubMed Central

Mercier, Patrick P; Lysaght, Andrew C; Bandyopadhyay, Saurav; Chandrakasan, Anantha P; Stankovic, Konstantina M

2013-01-01

Endocochlear potential (EP) is a battery-like electrochemical gradient found in and actively maintained by the inner ear1,2. Here we demonstrate that the mammalian EP can be used as a power source for electronic devices. We achieved this by designing an anatomically sized, ultra-low quiescent-power energy harvester chip integrated with a wireless sensor capable of monitoring the EP itself. Although other forms of in vivo energy harvesting have been described in lower organisms3-5, and thermoelectric6, piezoelectric7 and biofuel8,9 devices are promising for mammalian applications, there have been few, if any, in vivo demonstrations in the vicinity of the ear, eye and brain. In this work, the chip extracted a minimum of 1.12 nW from the EP of a guinea pig for up to 5 h, enabling a 2.4 GHz radio to transmit measurement of the EP every 40–360 s. With future optimization of electrode design, we envision using the biologic battery in the inner ear to power chemical and molecular sensors, or drug-delivery actuators for diagnosis and therapy of hearing loss and other disorders. PMID:23138225

HPN-07, a free radical spin trapping agent, protects against functional, cellular and electrophysiological changes in the cochlea induced by acute acoustic trauma

PubMed Central

Hu, Ning; Du, Xiaoping; Li, Wei; West, Matthew B.; Choi, Chul-Hee; Floyd, Robert; Kopke, Richard D.

2017-01-01

Oxidative stress is considered a major cause of the structural and functional changes associated with auditory pathologies induced by exposure to acute acoustic trauma AAT). In the present study, we examined the otoprotective effects of 2,4-disulfophenyl-N-tert-butylnitrone (HPN-07), a nitrone-based free radical trap, on the physiological and cellular changes in the auditory system of chinchilla following a six-hour exposure to 4 kHz octave band noise at 105 dB SPL. HPN-07 has been shown to suppress oxidative stress in biological models of a variety of disorders. Our results show that administration of HPN-07 beginning four hours after acoustic trauma accelerated and enhanced auditory/cochlear functional recovery, as measured by auditory brainstem responses (ABR), distortion product otoacoustic emissions (DPOAE), compound action potentials (CAP), and cochlear microphonics (CM). The normally tight correlation between the endocochlear potential (EP) and evoked potentials of CAP and CM were persistently disrupted after noise trauma in untreated animals but returned to homeostatic conditions in HPN-07 treated animals. Histological analyses revealed several therapeutic advantages associated with HPN-07 treatment following AAT, including reductions in inner and outer hair cell loss; reductions in AAT-induced loss of calretinin-positive afferent nerve fibers in the spiral lamina; and reductions in fibrocyte loss within the spiral ligament. These findings support the conclusion that early intervention with HPN-07 following an AAT efficiently blocks the propagative ototoxic effects of oxidative stress, thereby preserving the homeostatic and functional integrity of the cochlea. PMID:28832600

Identification of a key residue in Kv7.1 potassium channel essential for sensing external potassium ions.

PubMed

Wang, Wenying; Flores, Maria Cristina Perez; Sihn, Choong-Ryoul; Kim, Hyo Jeong; Zhang, Yinuo; Doyle, Karen J; Chiamvimonvat, Nipavan; Zhang, Xiao-Dong; Yamoah, Ebenezer N

2015-03-01

Kv7.1 voltage-gated K(+) (Kv) channels are present in the apical membranes of marginal cells of the stria vascularis of the inner ear, where they mediate K(+) efflux into the scala media (cochlear duct) of the cochlea. As such, they are exposed to the K(+)-rich (∼ 150 mM of external K(+) (K(+) e)) environment of the endolymph. Previous studies have shown that Kv7.1 currents are substantially suppressed by high K(+) e (independent of the effects of altering the electrochemical gradient). However, the molecular basis for this inhibition, which is believed to involve stabilization of an inactivated state, remains unclear. Using sequence alignment of S5-pore linkers of several Kv channels, we identified a key residue, E290, found in only a few Kv channels including Kv7.1. We used substituted cysteine accessibility methods and patch-clamp analysis to provide evidence that the ability of Kv7.1 to sense K(+) e depends on E290, and that the charge at this position is essential for Kv7.1's K(+) e sensitivity. We propose that Kv7.1 may use this feedback mechanism to maintain the magnitude of the endocochlear potential, which boosts the driving force to generate the receptor potential of hair cells. The implications of our findings transcend the auditory system; mutations at this position also result in long QT syndrome in the heart. © 2015 Wang et al.

How can the auditory efferent system protect our ears from noise-induced hearing loss? Let us count the ways

NASA Astrophysics Data System (ADS)

Marshall, Lynne; Miller, Judi A. Lapsley

2015-12-01

It is a cause for some debate as to how the auditory olivocochlear (OC) efferent system could protect hearing from noise trauma. In this review, we examined physiological research to find mechanisms that could effectively attenuate the response to sound. For each purported mechanism, we indicate which part of the OC-efferent system is responsible for the function and the site of action. These mechanisms include basilar-membrane phase shifts at high stimulus levels; changes in outer-hair-cell stiffness and phase lag associated with efferent slow effects; small decreases in endocochlear potentials causing small decreases in outer- and inner-hair-cell output; low-spontaneous-rate and medium-spontaneous-rate fibers showing OC-induced decrements at high levels; auditory-nerve initial-peak reduction; OC effect increasing over minutes; cholinergic activation of anti-apoptotic pathways; and anti-excitotoxicity. There are clearly multiple opportunities for the OC-efferent system to protect the inner ear from noise trauma. From further exploration into the mechanisms outlined here, as well as to-be-discovered mechanisms, we will gain a greater understanding of the protective nature of the OC-efferent system. These findings could aid our ability to design better predictive tests for people at risk for noise-induced hearing loss.

Molecular biology of hearing

PubMed Central

Stöver, Timo; Diensthuber, Marc

2012-01-01

The inner ear is our most sensitive sensory organ and can be subdivided into three functional units: organ of Corti, stria vascularis and spiral ganglion. The appropriate stimulus for the organ of hearing is sound, which travels through the external auditory canal to the middle ear where it is transmitted to the inner ear. The inner ear houses the hair cells, the sensory cells of hearing. The inner hair cells are capable of mechanotransduction, the transformation of mechanical force into an electrical signal, which is the basic principle of hearing. The stria vascularis generates the endocochlear potential and maintains the ionic homeostasis of the endolymph. The dendrites of the spiral ganglion form synaptic contacts with the hair cells. The spiral ganglion is composed of neurons that transmit the electrical signals from the cochlea to the central nervous system. In recent years there has been significant progress in research on the molecular basis of hearing. An increasing number of genes and proteins related to hearing are being identified and characterized. The growing knowledge of these genes contributes not only to greater appreciation of the mechanism of hearing but also to a deeper understanding of the molecular basis of hereditary hearing loss. This basic research is a prerequisite for the development of molecular diagnostics and novel therapies for hearing loss. PMID:22558056

QTL Mapping of Endocochlear Potential Differences between C57BL/6J and BALB/cJ mice.

PubMed

Ohlemiller, Kevin K; Kiener, Anna L; Gagnon, Patricia M

2016-06-01

We reported earlier that the endocochlear potential (EP) differs between C57BL/6J (B6) and BALB/cJ (BALB) mice, being lower in BALBs by about 10 mV (Ohlemiller et al. Hear Res 220: 10-26, 2006). This difference corresponds to strain differences with respect to the density of marginal cells in cochlear stria vascularis. After about 1 year of age, BALB mice also tend toward EP reduction that correlates with further marginal cell loss. We therefore suggested that early sub-clinical features of the BALB stria vascularis may predispose these mice to a condition modeling Schuknecht's strial presbycusis. We further reported (Ohlemiller et al. J Assoc Res Otolaryngol 12: 45-58, 2011) that the acute effects of a 2-h 110 dB SPL noise exposure differ between B6 and BALB mice, such that the EP remains unchanged in B6 mice, but is reduced by 40-50 mV in BALBs. In about 25 % of BALBs, the EP does not completely recover, so that permanent EP reduction may contribute to noise-induced permanent threshold shifts in BALBs. To identify genes and alleles that may promote natural EP variation as well as noise-related EP reduction in BALB mice, we have mapped related quantitative trait loci (QTLs) using 12 recombinant inbred (RI) strains formed from B6 and BALB (CxB1-CxB12). EP and strial marginal cell density were measured in B6 mice, BALB mice, their F1 hybrids, and RI mice without noise exposure, and 1-3 h after broadband noise (4-45 kHz, 110 dB SPL, 2 h). For unexposed mice, the strain distribution patterns for EP and marginal cell density were used to generate preliminary QTL maps for both EP and marginal cell density. Six QTL regions were at least statistically suggestive, including a significant QTL for marginal cell density on chromosome 12 that overlapped a weak QTL for EP variation. This region, termed Maced (Marginal cell density QTL) supports the notion of marginal cell density as a genetically influenced contributor to natural EP variation. Candidate genes for Maced notably include Foxg1, Foxa1, Akap6, Nkx2-1, and Pax9. Noise exposure produced significant EP reductions in two RI strains as well as significant EP increases in two RI strains. QTL mapping of the EP in noise-exposed RI mice yielded four suggestive regions. Two of these overlapped with QTL regions we previously identified for noise-related EP reduction in CBA/J mice (Ohlemiller et al. Hear Res 260: 47-53, 2010) on chromosomes 5 and 18 (Nirep). The present map may narrow the Nirep interval to a ~10-Mb region of proximal Chr. 18 that includes Zeb1, Arhgap12, Mpp7, and Gjd4. This study marks the first exploration of natural gene variants that modulate the EP. Their orthologs may underlie some human hearing loss that originates in the lateral wall.

Virally mediated Kcnq1 gene replacement therapy in the immature scala media restores hearing in a mouse model of human Jervell and Lange-Nielsen deafness syndrome

PubMed Central

Chang, Qing; Wang, Jianjun; Li, Qi; Kim, Yeunjung; Zhou, Binfei; Wang, Yunfeng; Li, Huawei; Lin, Xi

2015-01-01

Mutations in the potassium channel subunit KCNQ1 cause the human severe congenital deafness Jervell and Lange-Nielsen (JLN) syndrome. We applied a gene therapy approach in a mouse model of JLN syndrome (Kcnq1−/− mice) to prevent the development of deafness in the adult stage. A modified adeno-associated virus construct carrying a Kcnq1 expression cassette was injected postnatally (P0–P2) into the endolymph, which resulted in Kcnq1 expression in most cochlear marginal cells where native Kcnq1 is exclusively expressed. We also found that extensive ectopic virally mediated Kcnq1 transgene expression did not affect normal cochlear functions. Examination of cochlear morphology showed that the collapse of the Reissner’s membrane and degeneration of hair cells (HCs) and cells in the spiral ganglia were corrected in Kcnq1−/− mice. Electrophysiological tests showed normal endocochlear potential in treated ears. In addition, auditory brainstem responses showed significant hearing preservation in the injected ears, ranging from 20 dB improvement to complete correction of the deafness phenotype. Our results demonstrate the first successful gene therapy treatment for gene defects specifically affecting the function of the stria vascularis, which is a major site affected by genetic mutations in inherited hearing loss. PMID:26084842

Virally mediated Kcnq1 gene replacement therapy in the immature scala media restores hearing in a mouse model of human Jervell and Lange-Nielsen deafness syndrome.

PubMed

Chang, Qing; Wang, Jianjun; Li, Qi; Kim, Yeunjung; Zhou, Binfei; Wang, Yunfeng; Li, Huawei; Lin, Xi

2015-08-01

Mutations in the potassium channel subunit KCNQ1 cause the human severe congenital deafness Jervell and Lange-Nielsen (JLN) syndrome. We applied a gene therapy approach in a mouse model of JLN syndrome (Kcnq1(-/-) mice) to prevent the development of deafness in the adult stage. A modified adeno-associated virus construct carrying a Kcnq1 expression cassette was injected postnatally (P0-P2) into the endolymph, which resulted in Kcnq1 expression in most cochlear marginal cells where native Kcnq1 is exclusively expressed. We also found that extensive ectopic virally mediated Kcnq1 transgene expression did not affect normal cochlear functions. Examination of cochlear morphology showed that the collapse of the Reissner's membrane and degeneration of hair cells (HCs) and cells in the spiral ganglia were corrected in Kcnq1(-/-) mice. Electrophysiological tests showed normal endocochlear potential in treated ears. In addition, auditory brainstem responses showed significant hearing preservation in the injected ears, ranging from 20 dB improvement to complete correction of the deafness phenotype. Our results demonstrate the first successful gene therapy treatment for gene defects specifically affecting the function of the stria vascularis, which is a major site affected by genetic mutations in inherited hearing loss. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

BAAV mediated GJB2 gene transfer restores gap junction coupling in cochlear organotypic cultures from deaf Cx26Sox10Cre mice.

PubMed

Crispino, Giulia; Di Pasquale, Giovanni; Scimemi, Pietro; Rodriguez, Laura; Galindo Ramirez, Fabian; De Siati, Romolo Daniele; Santarelli, Rosa Maria; Arslan, Edoardo; Bortolozzi, Mario; Chiorini, John A; Mammano, Fabio

2011-01-01

The deafness locus DFNB1 contains GJB2, the gene encoding connexin26 and GJB6, encoding connexin30, which appear to be coordinately regulated in the inner ear. In this work, we investigated the expression and function of connexin26 and connexin30 from postnatal day 5 to adult age in double transgenic Cx26(Sox10Cre) mice, which we obtained by crossing connexin26 floxed mice with a deleter Sox10-Cre line. Cx26(Sox10Cre) mice presented with complete connexin26 ablation in the epithelial gap junction network of the cochlea, whereas connexin30 expression was developmentally delayed; immunolabeling patterns for both connexins were normal in the cochlear lateral wall. In vivo electrophysiological measurements in Cx26(Sox10Cre) mice revealed profound hearing loss accompanied by reduction of endocochlear potential, and functional experiments performed in postnatal cochlear organotypic cultures showed impaired gap junction coupling. Transduction of these cultures with a bovine adeno associated virus vector restored connexin26 protein expression and rescued gap junction coupling. These results suggest that restoration of normal connexin levels by gene delivery via recombinant adeno associated virus could be a way to rescue hearing function in DFNB1 mouse models and, in future, lead to the development of therapeutic interventions in humans.

A comparison of dehydration effects of V2-antagonist (OPC-31260) on the inner ear between systemic and round window applications.

PubMed

Takeda, Taizo; Takeda, Setsuko; Kakigi, Akinobu; Okada, Teruhiko; Nishioka, Rie; Taguchi, Daizo

2006-08-01

V2-antagonist (OPC-31260 (OPC)) application to the scala tympani reduced endolymphatic hydrops. In the present study, we investigated whether systemic administration or local infusion via the round window (RW application) of OPC would be more suitable for clinical use. In Experiment 1, the increase ratios of the cross-sectional area of the scala media of experimentally induced endolymphatic hydrops were quantitatively assessed among four groups of non-OPC application, RW application of xanthan gum, systemic application of OPC and RW application of OPC. In Experiment 2, the effects of systemic and RW applications of OPC on plasma vasopressin (p-VP) concentrations and plasma osmolality (p-OSM) were investigated. In Experiment 3, endocochlear DC potential (EP) was measured in guinea pigs with the RW application of OPC. Electron microscopic observations of the stria vascularis and the hair cells were also made. Both systemic and RW applications of OPC significantly reduced endolymphatic hydrops. However, systemic application resulted in the distension of the Reissner's membrane in the non-operated ear, which seemed to be caused by elevated p-VP levels resulting from the systemic application of OPC. In contrast, RW application of OPC produced no apparent toxic effects in the inner ear, as indicated electrophysiological or morphological changes. Thus, drug delivery via the round window is more useful for the clinical application of OPC for medical decompression.

Creation of miniature pig model of human Waardenburg syndrome type 2A by ENU mutagenesis.

PubMed

Hai, Tang; Guo, Weiwei; Yao, Jing; Cao, Chunwei; Luo, Ailing; Qi, Meng; Wang, Xianlong; Wang, Xiao; Huang, Jiaojiao; Zhang, Ying; Zhang, Hongyong; Wang, Dayu; Shang, Haitao; Hong, Qianlong; Zhang, Rui; Jia, Qitao; Zheng, Qiantao; Qin, Guosong; Li, Yongshun; Zhang, Tao; Jin, Weiwu; Chen, Zheng-Yi; Wang, Hongmei; Zhou, Qi; Meng, Anming; Wei, Hong; Yang, Shiming; Zhao, Jianguo

2017-11-01

Human Waardenburg syndrome 2A (WS2A) is a dominant hearing loss (HL) syndrome caused by mutations in the microphthalmia-associated transcription factor (MITF) gene. In mouse models with MITF mutations, WS2A is transmitted in a recessive pattern, which limits the study of hearing loss (HL) pathology. In the current study, we performed ENU (ethylnitrosourea) mutagenesis that resulted in substituting a conserved lysine with a serine (p. L247S) in the DNA-binding domain of the MITF gene to generate a novel miniature pig model of WS2A. The heterozygous mutant pig (MITF +/L247S ) exhibits a dominant form of profound HL and hypopigmentation in skin, hair, and iris, accompanied by degeneration of stria vascularis (SV), fused hair cells, and the absence of endocochlear potential, which indicate the pathology of human WS2A. Besides hypopigmentation and bilateral HL, the homozygous mutant pig (MITF L247S/L247S ) and CRISPR/Cas9-mediated MITF bi-allelic knockout pigs both exhibited anophthalmia. Three WS2 patients carrying MITF mutations adjacent to the corresponding region were also identified. The pig models resemble the clinical symptom and molecular pathology of human WS2A patients perfectly, which will provide new clues for better understanding the etiology and development of novel treatment strategies for human HL.

The endocochlear potential as an indicator of reticular lamina integrity after noise exposure in mice.

PubMed

Ohlemiller, Kevin K; Kaur, Tejbeer; Warchol, Mark E; Withnell, Robert H

2018-04-01

The endocochlear potential (EP) provides part of the electrochemical drive for sound-driven currents through cochlear hair cells. Intense noise exposure (110 dB SPL, 2 h) differentially affects the EP in three inbred mouse strains (C57BL/6 [B6], CBA/J [CBA], BALB/cJ [BALB]) (Ohlemiller and Gagnon, 2007, Hearing Research 224:34-50; Ohlemiller et al., 2011, JARO 12:45-58). At least for mice older than 3 mos, B6 mice are unaffected, CBA mice show temporary EP reduction, and BALB mice may show temporary or permanent EP reduction. EP reduction was well correlated with histological metrics for injury to stria vascularis and spiral ligament, and little evidence was found for holes or tears in the reticular lamina that might 'short out' the EP. Thus we suggested that the genes and processes that underlie the strain EP differences primarily impact cochlear lateral wall, not the organ of Corti. Our previous work did not test the range of noise exposure conditions over which strain differences apply. It therefore remained possible that the relation between exposure severity and acute EP reduction simply has a higher exposure threshold in B6 mice compared to CBA and BALB. We also did not test for age dependence. It is well established that young adult animals are especially vulnerable to noise-induced permanent threshold shifts (NIPTS). It is unknown, however, whether heightened vulnerability of the lateral wall contributes to this condition. The present study extends our previous work to multiple noise exposure levels and durations, and explicitly compares young adult (6-7 wks) and older mice (>4 mos). We find that the exposure level-versus-acute EP relation is dramatically strain-dependent, such that B6 mice widely diverge from both CBA and BALB. For all three strains, however, acute EP reduction is greater in young mice. Above 110 dB SPL, all mice exhibited rapid and severe EP reduction that is likely related to tearing of the reticular lamina. By contrast, EP-versus-noise duration examined at 104 dB suggested that different processes contribute to EP reduction in young and older mice. The average EP falls to a constant level after ∼7.5 min in older mice, but progressively decreases with further exposure in young mice. Confocal microscopy of organ of Corti surface preparations stained for phalloidin and zonula occludens-1 (ZO-1) indicated this corresponds to rapid loss of outer hair cells (OHCs) and formation of both holes and tears in the reticular lamina of young mice. In addition, when animals exposed at 119 dB were allowed to recover for 1 mo, only young B6 mice showed collapse of the EP to ≤5 mV. Confocal analysis suggested novel persistent loss of tight junctions in the lateral organ of Corti. This may allow paracellular leakage that permanently reduces the EP. From our other findings, we propose that noise-related lateral wall pathology in young CBA and BALB mice promotes hair cell loss and opening of the reticular lamina. The heightened vulnerability of young adult animals to noise exposure may in part reflect special sensitivity of the organ of Corti to acute lateral wall dysfunction at younger ages. This feature appears genetically modifiable. Copyright © 2018 Elsevier B.V. All rights reserved.

A Point Mutation in the Gene for Asparagine-Linked Glycosylation 10B (Alg10b) Causes Nonsyndromic Hearing Impairment in Mice (Mus musculus)

PubMed Central

Probst, Frank J.; Corrigan, Rebecca R.; del Gaudio, Daniela; Salinger, Andrew P.; Lorenzo, Isabel; Gao, Simon S.; Chiu, Ilene; Xia, Anping

2013-01-01

The study of mouse hearing impairment mutants has led to the identification of a number of human hearing impairment genes and has greatly furthered our understanding of the physiology of hearing. The novel mouse mutant neurological/sensory 5 (nse5) demonstrates a significantly reduced or absent startle response to sound and is therefore a potential murine model of human hearing impairment. Genetic analysis of 500 intercross progeny localized the mutant locus to a 524 kilobase (kb) interval on mouse chromosome 15. A missense mutation in a highly-conserved amino acid was found in the asparagine-linked glycosylation 10B gene (Alg10b), which is within the critical interval for the nse5 mutation. A 20.4 kb transgene containing a wildtype copy of the Alg10b gene rescued the mutant phenotype in nse5/nse5 homozygous animals, confirming that the mutation in Alg10b is responsible for the nse5/nse5 mutant phenotype. Homozygous nse5/nse5 mutants had abnormal auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), and cochlear microphonics (CMs). Endocochlear potentials (EPs), on the other hand, were normal. ABRs and DPOAEs also confirmed the rescue of the mutant nse5/nse5 phenotype by the wildtype Alg10b transgene. These results suggested a defect in the outer hair cells of mutant animals, which was confirmed by histologic analysis. This is the first report of mutation in a gene involved in the asparagine (N)-linked glycosylation pathway causing nonsyndromic hearing impairment, and it suggests that the hearing apparatus, and the outer hair cells in particular, are exquisitely sensitive to perturbations of the N-linked glycosylation pathway. PMID:24303013

Characterization of slow-cycling cells in the mouse cochlear lateral wall

PubMed Central

Ogawa, Kaoru

2017-01-01

Cochlear spiral ligament fibrocytes (SLFs) play essential roles in the physiology of hearing including ion recycling and the generation of endocochlear potential. In adult animals, SLFs can repopulate after damages, yet little is known about the characteristics of proliferating cells that support SLFs’ self-renewal. Here we report in detail about the characteristics of cycling cells in the spiral ligament (SL). Fifteen P6 mice and six noise-exposed P28 mice were injected with 5-bromo-2′-deoxyuridine (BrdU) for 7 days and we chased BrdU retaining cells for as long as 60 days. Immunohistochemistry revealed that the BrdU positive IB4 (an endotherial marker) negative cells expressed an early SLF marker Pou3f4 but negative for cleaved-Caspase 3. Marker studies revealed that type 3 SLFs displayed significantly higher percentage of BrdU+ cells compared to other subtypes. Notably, the cells retained BrdU until P72, demonstrating they were dividing slowly. In the noise-damaged mice, in contrast to the loss of the other types, the number of type 3 SLFs did not altered and the BrdU incorporating- phosphorylated Histone H3 positive type 3 cells were increased from day 1 to 14 after noise exposure. Furthermore, the cells repopulating type 1 area, where the cells diminished profoundly after damage, were positive for the type 3 SLF markers. Collectively, in the latral wall of the cochlea, type 3 SLFs have the stem cell capacity and may contribute to the endogenous regeneration of lateral wall spiral ligament. Manipulating type 3 cells may be employed for potential regenerative therapies. PMID:28632772

A mouse model for degeneration of the spiral ligament.

PubMed

Kada, Shinpei; Nakagawa, Takayuki; Ito, Juichi

2009-06-01

Previous studies have indicated the importance of the spiral ligament (SL) in the pathogenesis of sensorineural hearing loss. The aim of this study was to establish a mouse model for SL degeneration as the basis for the development of new strategies for SL regeneration. We injected 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase, at various concentrations into the posterior semicircular canal of adult C57BL/6 mice. Saline-injected animals were used as controls. Auditory function was monitored by measurements of auditory brain stem responses (ABRs). On postoperative day 14, cochlear specimens were obtained after the measurement of the endocochlear potential (EP). Animals that were injected with 5 or 10 mM 3-NP showed a massive elevation of ABR thresholds along with extensive degeneration of the cochleae. Cochleae injected with 1 mM 3-NP exhibited selective degeneration of the SL fibrocytes but alterations in EP levels and ABR thresholds were not of sufficient magnitude to allow for testing functional recovery after therapeutic interventions. Animals injected with 3 mM 3-NP showed a reduction of around 50% in the EP along with a significant loss of SL fibrocytes, although degeneration of spiral ganglion neurons and hair cells was still present in certain regions. These findings indicate that cochleae injected with 3 mM 3-NP may be useful in investigations designed to test the feasibility of new therapeutic manipulations for functional SL regeneration.

Cytomegalovirus (CMV) Infection Causes Degeneration of Cochlear Vasculature and Hearing Loss in a Mouse Model.

PubMed

Carraro, Mattia; Almishaal, Ali; Hillas, Elaine; Firpo, Matthew; Park, Albert; Harrison, Robert V

2017-04-01

Cytomegalovirus (CMV) infection is one of the most common causes of congenital hearing loss in children. We have used a murine model of CMV infection to reveal functional and structural cochlear pathogenesis. The cerebral cortex of Balb/c mice (Mus musculus) was inoculated with 2000 pfu (plaque forming units) of murine CMV on postnatal day 3. At 6 weeks of age, cochlear function was monitored using auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) measures. Histological assessment of cochlear vasculature using a corrosion cast technique was made at 8 weeks. Vascular casts of mCMV-damaged cochleas, and those of untreated control animals, were examined using scanning electron microscopy. We find very large variations in the degree of vascular damage in animals given identical viral injections (2000 pfu). The primary lesion caused by CMV infection is to the stria vascularis and to the adjacent spiral limbus capillary network. Capillary beds of the spiral ligament are generally less affected. The initial vascular damage is found in the mid-apical turn and appears to progress to more basal cochlear regions. After viral migration to the inner ear, the stria vascularis is the primary affected structure. We suggest that initial auditory threshold losses may relate to the poor development or maintenance of the endocochlear potential caused by strial dysfunction. Our increased understanding of the pathogenesis of CMV-related hearing loss is important for defining methods for early detection and treatment.

Cellular and Deafness Mechanisms Underlying Connexin Mutation-Induced Hearing Loss – A Common Hereditary Deafness

PubMed Central

Wingard, Jeffrey C.; Zhao, Hong-Bo

2015-01-01

Hearing loss due to mutations in the connexin gene family, which encodes gap junctional proteins, is a common form of hereditary deafness. In particular, connexin 26 (Cx26, GJB2) mutations are responsible for ~50% of non-syndromic hearing loss, which is the highest incidence of genetic disease. In the clinic, Cx26 mutations cause various auditory phenotypes ranging from profound congenital deafness at birth to mild, progressive hearing loss in late childhood. Recent experiments demonstrate that congenital deafness mainly results from cochlear developmental disorders rather than hair cell degeneration and endocochlear potential reduction, while late-onset hearing loss results from reduction of active cochlear amplification, even though cochlear hair cells have no connexin expression. However, there is no apparent, demonstrable relationship between specific changes in connexin (channel) functions and the phenotypes of mutation-induced hearing loss. Moreover, new experiments further demonstrate that the hypothesized K+-recycling disruption is not a principal deafness mechanism for connexin deficiency induced hearing loss. Cx30 (GJB6), Cx29 (GJC3), Cx31 (GJB3), and Cx43 (GJA1) mutations can also cause hearing loss with distinct pathological changes in the cochlea. These new studies provide invaluable information about deafness mechanisms underlying connexin mutation-induced hearing loss and also provide important information for developing new protective and therapeutic strategies for this common deafness. However, the detailed cellular mechanisms underlying these pathological changes remain unclear. Also, little is known about specific mutation-induced pathological changes in vivo and little information is available for humans. Such further studies are urgently required. PMID:26074771

Microbial community activities during establishment, performance, and decline of bench-scale passive treatment systems for mine drainage.

PubMed

Logan, Miranda V; Reardon, Kenneth F; Figueroa, Linda A; McLain, Jean E T; Ahmann, Dianne M

2005-11-01

Permeable reactive barrier (PRB) technology, in which sulfate-reducing bacteria (SRB) facilitate precipitation of metal sulfides, is a promising approach for remediation of sulfate- and metal-laden mine drainage. While PRBs are easily established, they often decline for reasons not well understood. SRB depend on or compete with multiple dynamic microbial populations within a PRB; as a result, performance depends on the changing PRB chemical composition and on succession and competition within the microbial community. To investigate these interactions, we constructed and monitored eight bench-scale PRBs to define periods of establishment, performance, and decline. We then conducted short-term batch studies, using substrate-supplemented column materials, on Days 0 (pre-establishment), 27 (establishment), 41 (performance), and 99 (decline) to reveal potential activities of cellulolytic bacteria, fermenters + anaerobic respirers, SRB, and methanogens. PRBs showed active sulfate reduction, with sulfate removal rates (SRR) of approximately 1-3 mol/m3/d, as well as effective removal of Zn2+. Potential activities of fermentative + anaerobic respiratory bacteria were initially high but diminished greatly during establishment and dropped further during performance and decline. In contrast, potential SRB activity rose during establishment, peaked during performance, and diminished as performance declined. Potential methanogen activity was low; in addition, SRB-methanogen substrate competition was shown not to limit SRB activity. Cellulolytic bacteria showed no substrate limitation at any time. However, fermenters experienced substrate limitation by Day 0, SRB by Day 27, and methanogens by Day 41, showing the dependence of each group on upstream populations to provide substrates. All potential activities, except methanogenesis, were ultimately limited by cellulose hydrolysis; in addition, all potential activities except methanogenesis declined substantially by Day 99, showing that long-term substrate deprivation strongly diminished the intrinsic capacity of the PRB community to perform.

Physiological role of L-type Ca2+ channels in marginal cells in the stria vascularis of guinea pigs.

PubMed

Inui, Takaki; Mori, Yoshiaki; Watanabe, Masahito; Takamaki, Atsuko; Yamaji, Junko; Sohma, Yoshiro; Yoshida, Ryotaro; Takenaka, Hiroshi; Kubota, Takahiro

2007-10-01

Using immunohistochemical and electrophysiological methods, we investigated the role of L-type Ca(2+) channels in the regulation of the endocochlear potential (EP) of the endolymphatic surface cells (ESC) of the guinea pig stria vascularis. The following findings were made: (1) Administration of 30 microg/ml nifedipine via a vertebral artery significantly suppressed the transient asphyxia-induced decrease in the EP (TAID) and the transient asphyxia-induced increase in the Ca(2+), referred to as TAIICa, concentration in the endolymph ([Ca](e)). (2) The endolymphatic administration of 1 microg/ml nifedipine significantly inhibited the TAID as well as the TAIICa. The endolymphatic administration of nifedipine (0.001-10 microg/ml) inhibited the TAID in a dose-dependent manner. (3) The endolymphatic administration of (+)-Bay K8644, an L-type Ca(2+) channel closer, significantly inhibited the TAID, whereas (-)-Bay K8644, an L-type Ca(2+) channel opener, caused a large decrease in the EP from approximately +75 mV to approximately +20 mV at 10 min after the endolymphatic administration. (4) By means of immunohistochemistry, a positive staining reaction with L-type Ca(2+) channels was detected in the marginal cells of the stria vascularis. (5) Under the high [Ca](e) condition, we examined the mechanism of the TAIICa and hypothesized that the TAIICa might have been caused by the decrease in the EP through a shunt pathway in the ESC. (6) The administration of nifedipine to the endolymph significantly inhibited the Ba(2+)-induced decrease in the EP. These findings support the view that L-type Ca(2+) channels in the marginal cells regulate the EP, but not directly the TAIICa.

SLC4A11 Prevents Osmotic Imbalance Leading to Corneal Endothelial Dystrophy, Deafness, and Polyuria*

PubMed Central

Gröger, Nicole; Fröhlich, Henning; Maier, Hannes; Olbrich, Andrea; Kostin, Sawa; Braun, Thomas; Boettger, Thomas

2010-01-01

Maintenance of ion concentration gradients is essential for the function of many organs, including the kidney, the cornea, and the inner ear. Ion concentrations and fluid content in the cornea are regulated by endothelial cells that separate the collagenous avascular corneal stroma from the anterior eye chamber. Failure to maintain correct ion concentrations leads to swelling and destruction of the cornea. In the inner ear, the stria vascularis is responsible for generating proper ion concentrations in the endolymph, which is essential for hearing. Mutations of SLC4A11 in humans lead to syndromes associated with corneal dystrophy and perceptive deafness. The molecular mechanisms underlying these symptoms are poorly understood, impeding therapeutic interventions. The ion transporter SLC4A11 mediates sodium-dependent transport of borate as well as flux of sodium and hydroxyl ions in vitro. Here, we show that SLC4A11 is expressed in the endothelial cells of the cornea where it prevents severe morphological changes of the cornea caused by increased sodium chloride concentrations in the stroma. In the inner ear, SLC4A11 is located in fibrocytes underlying the stria vascularis. Loss of SLC4A11 leads to morphological changes in the fibrocytes and deafness. We demonstrate that SLC4A11 is essential for the generation of the endocochlear potential but not for regulation of potassium concentrations in the endolymph. In the kidney, SLC4A11 is expressed in the thin descending limb of Henle loop. SLC4A11 is essential for urinary concentration, suggesting that SLC4A11 participates in the countercurrent multiplication that concentrates urine in the kidney medulla. PMID:20185830

ILDR1 null mice, a model of human deafness DFNB42, show structural aberrations of tricellular tight junctions and degeneration of auditory hair cells

PubMed Central

Morozko, Eva L.; Nishio, Ayako; Ingham, Neil J.; Chandra, Rashmi; Fitzgerald, Tracy; Martelletti, Elisa; Borck, Guntram; Wilson, Elizabeth; Riordan, Gavin P.; Wangemann, Philine; Forge, Andrew; Steel, Karen P.; Liddle, Rodger A.; Friedman, Thomas B.; Belyantseva, Inna A.

2015-01-01

In the mammalian inner ear, bicellular and tricellular tight junctions (tTJs) seal the paracellular space between epithelial cells. Tricellulin and immunoglobulin-like (Ig-like) domain containing receptor 1 (ILDR1, also referred to as angulin-2) localize to tTJs of the sensory and non-sensory epithelia in the organ of Corti and vestibular end organs. Recessive mutations of TRIC (DFNB49) encoding tricellulin and ILDR1 (DFNB42) cause human nonsyndromic deafness. However, the pathophysiology of DFNB42 deafness remains unknown. ILDR1 was recently reported to be a lipoprotein receptor mediating the secretion of the fat-stimulated cholecystokinin (CCK) hormone in the small intestine, while ILDR1 in EpH4 mouse mammary epithelial cells in vitro was shown to recruit tricellulin to tTJs. Here we show that two different mouse Ildr1 mutant alleles have early-onset severe deafness associated with a rapid degeneration of cochlear hair cells (HCs) but have a normal endocochlear potential. ILDR1 is not required for recruitment of tricellulin to tTJs in the cochlea in vivo; however, tricellulin becomes mislocalized in the inner ear sensory epithelia of ILDR1 null mice after the first postnatal week. As revealed by freeze-fracture electron microscopy, ILDR1 contributes to the ultrastructure of inner ear tTJs. Taken together, our data provide insight into the pathophysiology of human DFNB42 deafness and demonstrate that ILDR1 is crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs. PMID:25217574

Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics.

PubMed

Kale, Sushrut S; Olson, Elizabeth S

2015-12-15

Models of the active cochlea build upon the underlying passive mechanics. Passive cochlear mechanics is based on physical and geometrical properties of the cochlea and the fluid-tissue interaction between the cochlear partition and the surrounding fluid. Although the fluid-tissue interaction between the basilar membrane and the fluid in scala tympani (ST) has been explored in both active and passive cochleae, there was no experimental data on the fluid-tissue interaction on the scala media (SM) side of the partition. To this aim, we measured sound-evoked intracochlear pressure in SM close to the partition using micropressure sensors. All the SM pressure data are from passive cochleae, likely because the SM cochleostomy led to loss of endocochlear potential. Thus, these experiments are studies of passive cochlear mechanics. SM pressure close to the tissue showed a pattern of peaks and notches, which could be explained as an interaction between fast and slow (i.e., traveling wave) pressure modes. In several animals SM and ST pressure were measured in the same cochlea. Similar to previous studies, ST-pressure was dominated by a slow, traveling wave mode at stimulus frequencies in the vicinity of the best frequency of the measurement location, and by a fast mode above best frequency. Antisymmetric pressure between SM and ST supported the classic single-partition cochlear models, or a dual-partition model with tight coupling between partitions. From the SM and ST pressure we calculated slow and fast modes, and from active ST pressure we extrapolated the passive findings to the active case. The passive slow mode estimated from SM and ST data was low-pass in nature, as predicted by cochlear models. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Intracochlear Scala Media Pressure Measurement: Implications for Models of Cochlear Mechanics

PubMed Central

Kale, Sushrut S.; Olson, Elizabeth S.

2015-01-01

Models of the active cochlea build upon the underlying passive mechanics. Passive cochlear mechanics is based on physical and geometrical properties of the cochlea and the fluid-tissue interaction between the cochlear partition and the surrounding fluid. Although the fluid-tissue interaction between the basilar membrane and the fluid in scala tympani (ST) has been explored in both active and passive cochleae, there was no experimental data on the fluid-tissue interaction on the scala media (SM) side of the partition. To this aim, we measured sound-evoked intracochlear pressure in SM close to the partition using micropressure sensors. All the SM pressure data are from passive cochleae, likely because the SM cochleostomy led to loss of endocochlear potential. Thus, these experiments are studies of passive cochlear mechanics. SM pressure close to the tissue showed a pattern of peaks and notches, which could be explained as an interaction between fast and slow (i.e., traveling wave) pressure modes. In several animals SM and ST pressure were measured in the same cochlea. Similar to previous studies, ST-pressure was dominated by a slow, traveling wave mode at stimulus frequencies in the vicinity of the best frequency of the measurement location, and by a fast mode above best frequency. Antisymmetric pressure between SM and ST supported the classic single-partition cochlear models, or a dual-partition model with tight coupling between partitions. From the SM and ST pressure we calculated slow and fast modes, and from active ST pressure we extrapolated the passive findings to the active case. The passive slow mode estimated from SM and ST data was low-pass in nature, as predicted by cochlear models. PMID:26682824

Ectopic Mineralization in the Middle Ear and Chronic Otitis Media with Effusion Caused by RPL38 Deficiency in the Tail-short (Ts) Mouse*

PubMed Central

Noben-Trauth, Konrad; Latoche, Joseph R.

2011-01-01

Inflammation of the middle ear cavity (otitis media) and the abnormal deposition of bone at the otic capsule are common causes of conductive hearing impairment in children and adults. Although a host of environmental factors can contribute to these conditions, a genetic predisposition has an important role as well. Here, we analyze the Tail-short (Ts) mouse, which harbors a spontaneous semi-dominant mutation that causes skeletal defects and hearing loss. By genetic means, we show that the Ts phenotypes arise from an 18-kb deletion/insertion of the Rpl38 gene, encoding a ribosomal protein of the large subunit. We show that Ts mutants exhibit significantly elevated auditory-brain stem response thresholds and reduced distortion-product otoacoustic emissions, in the presence of normal endocochlear potentials and typical inner ear histology suggestive of a conductive hearing impairment. We locate the cause of the hearing impairment to the middle ear, demonstrating over-ossification at the round window ridge, ectopic deposition of cholesterol crystals in the middle ear cavity, enlarged Eustachian tube, and chronic otitis media with effusion all beginning at around 3 weeks after birth. Using specific antisera, we demonstrate that Rpl38 is an ∼8-kDa protein that is predominantly expressed in mature erythrocytes. Finally, using an Rpl38 cDNA transgene, we rescue the Ts phenotypes. Together, these data present a previously uncharacterized combination of interrelated middle ear pathologies and suggest Rpl38 deficiency as a model to dissect the causative relationships between neo-ossification, cholesterol crystal deposition, and Eustachian tubes in the etiology of otitis media. PMID:21062742

Identifying stressed and potentially unstable trees by aerial photography on Ohio's highways.

DOT National Transportation Integrated Search

2002-10-01

Trees are valuable assets and potential liabilities in a man dominated situations such as : along Ohios highways. While trees are often long-lived, they must decline and die like : any other living thing. Decline may be nearly instantaneous as in ...

Identifying stressed and potentially unstable trees by aerial photography on Ohio's highways : executive summary.

DOT National Transportation Integrated Search

2002-10-01

Trees are valuable assets and potential liabilities in a man dominated situations such as along Ohios highways. While trees are often long-lived, they must decline and die like any other living thing. Decline may be nearly instantaneous as in a li...

Global amphibian declines: perspectives from the United States and beyond

USGS Publications Warehouse

Densmore, Christine L.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

2011-01-01

Over recent decades, amphibians have experienced population declines, extirpations and species-level extinctions at an alarming rate. Numerous potential etiologies for amphibian declines have been postulated including climate and habitat degradation. Other potential anthropogenic causes including overexploitation and the frequent introductions of invasive predatory species have also been blamed for amphibian declines. Still other underlying factors may include infectious diseases caused by the chytrid fungus Batrachochytrium dendrobatidis, pathogenic viruses (Ranavirus), and other agents. It is nearly certain that more than one etiology is to blame for the majority of the global amphibian declines, and that these causal factors include some combination of climatological or physical habitat destabilization and infectious disease, most notably chytridiomycosis. Scientific research efforts are aimed at elucidating these etiologies on local, regional, and global scales that we might better understand and counteract the driving forces behind amphibian declines. Conservation efforts as outlined in the Amphibian Conservation Action Plan of 2005 are also being made to curtail losses and prevent further extinctions wherever possible.

Sexual differences in the ecology and habitat selection of western toads (Bufo boreas) in northeastern Oregon.

Treesearch

Evelyn L. Bull

2006-01-01

Several species of toads (family Bufonidae), including the Western Toad (bufo boreas) have declined in the Western United States. Information on toad ecology and habitat use is essential to determine potential causes for population declines, as is the potential relationship between this information and disturbance events. Aspects of western toad...

Declining scaup populations: A retrospective analysis of long-term population and harvest survey data

USGS Publications Warehouse

Afton, A.D.; Anderson, M.G.

2001-01-01

We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the continental scaup breeding population has declined over the last 20 years, with widespread and consistent declines within surveyed areas of the Canadian western boreal forest where most lesser scaup breed; (2) sex ratios of lesser scaup in the U.S. harvest have increased (more males now relative to females); and (3) age ratios of lesser scaup in the U.S. harvest have declined (fewer immatures now relative to adults), especially in the midcontinent region. We interpreted these major findings as evidence that (1) recruitment of lesser scaup has declined over the last 20 years, particularly in the Canadian western boreal forest; and (2) survival of female lesser scaup has declined relative to that of males. We found little evidence that harvest was associated with the scaup population decline. Our findings underscore the need for both improvements and changes to population survey procedures and new research to discriminate among various hypotheses explaining the recent scaup population decline.

Trajectories of age-related cognitive decline and potential associated factors of cognitive function in senior citizens of Beijing.

PubMed

Li, He; Lv, Chenlong; Zhang, Ting; Chen, Kewei; Chen, Chuansheng; Gai, Guozhong; Hu, Liangping; Wang, Yongyan; Zhang, Zhanjun

2014-01-01

With a longer life expectancy and an increased prevalence of neurodegenerative diseases, investigations on trajectories of cognitive aging have become exciting and promising. This study aimed to estimate the patterns of age-related cognitive decline and the potential associated factors of cognitive function in community-dwelling residents of Beijing, China. In this study, 1248 older adults aged 52-88 years [including 175 mild cognitive impairment (MCI) subjects] completed a battery of neuropsychological scales. The personal information, including demographic information, medical history, eating habits, lifestyle regularity and leisure activities, was also collected. All cognitive function exhibited an agerelated decline in normal volunteers. Piece-wise linear fitting results suggested that performance on the Auditory Verbal Learning Test remained stable until 58 years of age and continued to decline thereafter. The decline in processing speed and executive function began during the early 50's. Scores on visual-spatial and language tests declined after 66 years of age. The decline stage of the general mental status ranged from 63 to 70 years of age. However, the MCI group did not exhibit an obvious age-related decline in most cognitive tests. Multivariate linear regression analyses indicated that education, gender, leisure activities, diabetes and eating habits were associated with cognitive abilities. These results indicated various trajectories of age-related decline across multiple cognitive domains. We also found different patterns of agerelated cognitive decline between MCI and normal elderly. These findings could help improve the guidance of cognitive intervention program and have implications for public policy issues.

Functional expression of P2X4 receptor in capillary endothelial cells of the cochlear spiral ligament and its role in regulating the capillary diameter.

PubMed

Wu, T; Dai, M; Shi, X R; Jiang, Z G; Nuttall, A L

2011-07-01

The cochlear lateral wall generates the endocochlear potential (EP), which creates a driving force for the hair cell transduction current and is essential for normal hearing. Blood flow at the cochlear lateral wall is critically important for maintaining the EP. The vulnerability of the EP to hypoxia suggests that the blood flow in the cochlear lateral wall is dynamically and precisely regulated to meet the changing metabolic needs of the cochlear lateral wall. It has been reported that ATP, an important extracellular signaling molecule, plays an essential role in regulating cochlear blood flow. However, the cellular mechanism underlying ATP-induced regional blood flow changes has not been investigated. In the current study, we demonstrate that 1) the P2X4 receptor is expressed in endothelial cells (ECs) of spiral ligament (SL) capillaries. 2) ATP elicits a characteristic current through P2X4 on ECs in a dose-dependent manner (EC(50) = 0.16 mM). The ATP current has a reversal potential at ∼0 mV; is inhibited by 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD), LaCl(3), pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt hydrate (PPADS), and extracellular acidosis; and is less sensitive to α,β-methyleneadenosine 5'-triphosphate (α,β-MeATP) and 2'- and 3'-O-(4-benzoyl-benzoyl) adenosine 5'-triphosphate (BzATP). 3) ATP elicits a transient increase of intracellular Ca(2+) in ECs. 4) In accordance with the above in vitro findings, perilymphatic ATP (1 mM) caused dilation in SL capillaries in vivo by 11.5%. N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME), a nonselective inhibitor of nitric oxide synthase, or 5-BDBD, the specific P2X4 inhibitor, significantly blocked the dilation. These findings support our hypothesis that extracellular ATP regulates cochlear lateral blood flow through P2X4 activation in ECs.

Memory Decline in Peri- and Post-menopausal Women: The Potential of Mind–Body Medicine to Improve Cognitive Performance

PubMed Central

Sliwinski, Jim R; Johnson, Aimee K; Elkins, Gary R

2014-01-01

Cognitive decline is a frequent complaint during the menopause transition and among post-menopausal women. Changes in memory correspond with diminished estrogen production. Further, many peri- and post-menopausal women report sleep concerns, depression, and hot flashes, and these factors may contribute to cognitive decline. Hormone therapy can increase estrogen but is contraindicated for many women. Mind–body medicine has been shown to have beneficial effects on sleep, mood, and hot flashes, among post-menopausal women. Further, mind–body medicine holds potential in addressing symptoms of cognitive decline post-menopause. This study proposes an initial framework for how mind–body interventions may improve cognitive performance and inform future research seeking to identify the common and specific factors associated with mind–body medicine for addressing memory decline in peri- and post-menopausal women. It is our hope that this article will eventually lead to a more holistic and integrative approach to the treatment of cognitive deficits in peri- and post-menopausal women. PMID:25125972

β-Amyloid binding in elderly subjects with declining or stable episodic memory function measured with PET and [¹¹C]AZD2184.

PubMed

Mattsson, Patrik; Forsberg, Anton; Persson, Jonas; Nyberg, Lars; Nilsson, Lars-Göran; Halldin, Christer; Farde, Lars

2015-09-01

Cognitive decline has been suggested as an early marker for later onset of Alzheimer's disease. We therefore explored the relationship between decline in episodic memory and β-amyloid using positron emission tomography (PET) and [(11)C]AZD2184, a radioligand with potential to detect low levels of amyloid deposits. Healthy elderly subjects with declining (n = 10) or stable (n = 10) episodic memory over 15 years were recruited from the population-based Betula study and examined with PET. Brain radioactivity was measured after intravenous administration of [(11)C]AZD2184. The binding potential BP ND was calculated using linear graphical analysis with the cerebellum as reference region. The binding of [(11)C]AZD2184 in total grey matter was generally low in the declining group, whereas some binding could be observed in the stable group. Mean BP ND was significantly higher in the stable group compared to the declining group (p = 0.019). An observation was that the three subjects with the highest BP ND were ApoE ε4 allele carriers. We conclude that cognitive decline in the general population does not seem to stand by itself as an early predictor for amyloid deposits.

The link between rapid enigmatic amphibian decline and the globally emerging chytrid fungus.

PubMed

Lötters, Stefan; Kielgast, Jos; Bielby, Jon; Schmidtlein, Sebastian; Bosch, Jaime; Veith, Michael; Walker, Susan F; Fisher, Matthew C; Rödder, Dennis

2009-09-01

Amphibians are globally declining and approximately one-third of all species are threatened with extinction. Some of the most severe declines have occurred suddenly and for unknown reasons in apparently pristine habitats. It has been hypothesized that these "rapid enigmatic declines" are the result of a panzootic of the disease chytridiomycosis caused by globally emerging amphibian chytrid fungus. In a Species Distribution Model, we identified the potential distribution of this pathogen. Areas and species from which rapid enigmatic decline are known significantly overlap with those of highest environmental suitability to the chytrid fungus. We confirm the plausibility of a link between rapid enigmatic decline in worldwide amphibian species and epizootic chytridiomycosis.

Evaluation of soil saturation, soil chemistry, and early spring soil and air temperatures as risk factors in yellow-cedar decline.

Treesearch

D.V. D' Amore; P.E. Hennon

2006-01-01

Yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst.) is a valuable tree species that is experiencing a widespread decline and mortality in southeast Alaska. This study evaluated the relative importance of several potential risk factors associated with yellow-cedar decline: soil saturation, soil aluminum (Al) toxicity or calcium (Ca) deficiency...

Serum Micronutrient Concentrations and Decline in Physical Function Among Older Persons

PubMed Central

Bartali, Benedetta; Frongillo, Edward A.; Guralnik, Jack M.; Stipanuk, Martha H.; Allore, Heather G.; Cherubini, Antonio; Bandinelli, Stefania; Ferrucci, Luigi; Gill, Thomas M.

2009-01-01

Context Maintaining independence of older persons is a public health priority, and identifying the factors that contribute to decline in physical function is needed to prevent or postpone the disablement process. The potential deleterious effect of poor nutrition on decline in physical function in older persons is unclear. Objective To determine whether a low serum concentration of micronutrients is associated with subsequent decline in physical function among older men and women living in the community. Design, Setting, and Participants Longitudinal study of 698 community-living persons 65 years or older who were randomly selected from a population registry in Tuscany, Italy. Participants completed the baseline examination from November 1, 1998, through May 28, 2000, and the 3-year follow-up assessments from November 1, 2001, through March 30, 2003. Main Outcome Measure Decline in physical function was defined as a loss of at least 1 point in the Short Physical Performance Battery during the 3-year follow-up. Odds ratios (ORs) were calculated for the lowest quartile of each nutrient using the other 3 quartiles combined as the reference group. Two additional and complementary analytical approaches were used to confirm the validity of the results. Results The mean decline in the Short Physical Performance Battery score was 1.1 point. In a logistic regression analysis that was adjusted for potential confounders, only a low concentration of vitamin E (<1.1 μg/mL [<24.9 μmol/L]) was significantly associated with subsequent decline in physical function (OR, 1.62; 95% confidence interval, 1.11-2.36; P=.01 for association of lowest α-tocopherol quartile with at least a 1-point decline in physical function). In a general linear model, the concentration of vitamin E at baseline, when analyzed as a continuous measure, was significantly associated with the Short Physical Performance Battery score at follow-up after adjustment for potential confounders and Short Physical Performance Battery score at baseline (β=.023; P=.01). In a classification and regression tree analysis, age older than 81 years and vitamin E (in participants aged 70-80 years) were identified as the strongest determinants of decline in physical function (physical decline in 84% and 60%, respectively; misclassification error rate, 0.33). Conclusions These results provide empirical evidence that a low serum concentration of vitamin E is associated with subsequent decline in physical function among community-living older adults. Clinical trials may be warranted to determine whether an optimal concentration of vitamin E reduces functional decline and the onset of disability in older persons. PMID:18212315

The decline and fall of Type II error rates

Treesearch

Steve Verrill; Mark Durst

2005-01-01

For general linear models with normally distributed random errors, the probability of a Type II error decreases exponentially as a function of sample size. This potentially rapid decline reemphasizes the importance of performing power calculations.

Oak decline in the Boston Mountains, Arkansas, USA: Spatial and temporal patterns under two fire regimes

Treesearch

Martin A. Spetich; Hong S. He

2008-01-01

A spatially explicit forest succession and disturbance model is used to delineate the extent and dispersion of oak decline under two fire regimes over a 150-year period. The objectives of this study are to delineate potential current and future oak decline areas using species composition and age structure data in combination with ecological land types, and to...

Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands.

PubMed

Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A; van der Linden, Giel T J; Schaminée, Joop H J; Siepel, Henk; Kleijn, David

2014-12-09

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species.

Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands

PubMed Central

Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A.; van der Linden, Giel T. J.; Schaminée, Joop H. J.; Siepel, Henk; Kleijn, David

2014-01-01

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species. PMID:25422416

Co-ordination of growth, gas exchange and hydraulics define the carbon safety margin in tree species with contrasting drought strategies.

PubMed

Mitchell, P J; O'Grady, A P; Tissue, D T; Worledge, D; Pinkard, E A

2014-05-01

Gas exchange, growth, water transport and carbon (C) metabolism diminish during drought according to their respective sensitivities to declining water status. The timing of this sequence of declining physiological functions may determine how water and C relations compromise plant survival. In this paper, we test the hypothesis that the degree of asynchrony between declining C supply (photosynthesis) and C demand (growth and respiration) determines the rate and magnitude of changes in whole-plant non-structural carbohydrates (NSC) during drought. Two complementary experiments using two tree species (Eucalyptus globulus Labill. and Pinus radiata D. Don) with contrasting drought response strategies were performed to (i) assess changes in radial stem growth, transpiration, leaf water potential and gas exchange in response to chronic drought, and (ii) evaluate the concomitant impacts of these drought responses on the temporal patterns of NSC during terminal drought. The three distinct phases of water stress were delineated by thresholds of growth cessation and stomatal closure that defined the 'carbon safety margin' (i.e., the difference between leaf water potential when growth is zero and leaf water potential when net photosynthesis is zero). A wider C safety margin in E. globulus was defined by an earlier cessation of growth relative to photosynthesis that reduced the demand for NSC while maintaining C acquisition. By contrast, the narrower C safety margin in P. radiata was characterized by a synchronous decline in growth and photosynthesis, whereby growth continued under a declining supply of NSC from photosynthesis. The narrower C safety margin in P. radiata was associated with declines in starch concentrations after ∼ 90 days of chronic drought and significant depletion of starch in all organs at mortality. The observed divergence in the sensitivity of drought responses is indicative of a potential trade-off between maintaining hydraulic safety and adequate C availability. © The Author 2014. Published by Oxford University Press. All rights reserved.

Effects of perilymphatic pressure, sodium nitroprusside, and bupivacaine on cochlear fluid pH of guinea pigs.

PubMed

Suzuki, Masaaki; Kotani, Ryosuke

2015-01-01

Hydrostatic positive pressure and vasoconstrictor acidified the cochlear fluids, whereas the vasodilator made the fluids alkaline. CBF might play a role in regulating cochlea fluid pH. Cochlea fluid pH is highly dependent on the HCO3(-)/CO2 buffer system. Cochlear blood flow (CBF) supplies O2 and removes CO2. It is speculated that cochlear blood flow changes might affect the balance of the HCO3(-)/CO2 buffer system in the cochlea. It is known that the elevation of inner ear pressure decreases the CBF, and local application of vasodilating or vasoconstricting agents directly to the cochlea changes the CBF. The purpose of this study was to elucidate the effect of positive hydrostatic inner ear pressure and application of a vasodilator and vasoconstrictor of cochlear vessels on the pH of the endolymph and perilymph. The authors performed animal physiological experiments on 30 guinea pigs. Hydrostatic positive pressure was infused through a glass capillary tube inserted into the scala tympani of the basal turn. The vasodilator, nitric oxide donor (sodium nitroprusside; SNP), and the vasoconstrictor, bupivacaine, were placed topically onto the round window of the guinea pig cochlea. Endolymph pH (pHe) and endocochlear potential (EP) were monitored by double-barreled ion-selective microelectrodes in the second turn of the guinea pig cochlea. During the topical application study, scala vestibuli perilymph pH (pHv) was also measured simultaneously in the second turn. The application of hydrostatic positive pressure caused a decrease in pHe and EP. Positive perilymphatic pressure caused the endolymph to become acidic pressure-dependently. Application of 3.0% SNP evoked an increase in both the pHe and pHv, following by a gradual recovery to baseline levels. On the other hand, 0.5% bupivacaine caused a decrease in both the pHe and pHv. The EP during topical application showed slight, non-significant changes.

Spiral ligament and stria vascularis changes in cochlear otosclerosis: effect on hearing level.

PubMed

Doherty, Joni K; Linthicum, Fred H

2004-07-01

To investigate the effect of changes within the spiral ligament and stria vascularis on hearing in cochlear otosclerosis, we examined spiral ligament hyalinization, stria vascularis atrophy, and sensory hearing loss in cochlear otosclerosis and described changes in ion transport molecule expression. Retrospective. Tertiary referral center. Thirty-two cochleae from 24 temporal bone donors with histologic evidence of cochlear otosclerosis, including spiral ligament hyalinization. Audiography. Measurements of spiral ligament width, stria vascularis, and bone-conduction thresholds were compared by the amount of hyalinization. Expression of the ion transport molecules Na,K-ATPase, connexin 26, and carbonic anhydrase II were assessed by immunohistochemical techniques. Hyalinization most often involved the posterior basal turn (88%) and the posterior middle turn (27%). Spiral ligament hyalinization correlated significantly with stria vascularis atrophy in the posterior middle turn of the cochlea (rho = -0.63, p < 0.01). There was a trend toward a significant association in the posterior basal turn (rho = -0.31, p < 0.08). Bone-conduction thresholds at 2,000 and 4,000 Hz were significantly associated with the amount of stria vascularis atrophy (rho = -0.44, -0.40, p < 0.05). In addition, we observed decreased immunostaining for both carbonic anhydrase II with Type I fibrocytes and Na,K-ATPase with stria vascularis and Type II and Type IV fibrocytes of the spiral ligament in cochlear otosclerosis sections compared with normal cochlea. Na,K-ATPase staining within the stria vascularis was further decreased in the presence of spiral ligament hyalinization. No significant differences were seen with connexin 26 immunostaining. However, immunostaining results were somewhat inconsistent. These data suggest that spiral ligament structure and function are essential for stria vascularis survival. In addition, dampened expression of ion transport molecules within the spiral ligament and stria vascularis may disrupt potassium ion recycling, resulting in loss of endocochlear potential and sensory hearing loss.

Quantifying Coral Reef Ecosystem Services

EPA Science Inventory

Coral reefs have been declining during the last four decades as a result of both local and global anthropogenic stresses. Numerous research efforts to elucidate the nature, causes, magnitude, and potential remedies for the decline have led to the widely held belief that the recov...

Complexity versus certainty in understanding species’ declines

USGS Publications Warehouse

Sundstrom, Shana M.; Allen, Craig R.

2014-01-01

Traditional approaches to predict species declines (e.g. government processes or IUCN Red Lists), may be too simplistic and may therefore misguide management and conservation. Using complex systems approaches that account for scale-specific patterns and processes have the potential to overcome these limitations.

Has contemporary climate change played a role in population declines of the lizard Ctenophorus decresii from semi-arid Australia?

PubMed

Walker, Samantha; Stuart-Fox, Devi; Kearney, Michael R

2015-12-01

Whilst contemporary climatic changes are small in magnitude compared to those predicted for the coming decades, they have already been linked to species range shifts and local extinctions. Elucidating the drivers behind species' responses to contemporary climate change will better inform management strategies for vulnerable and pest species alike. A recent proposal to explain worldwide local extinctions in lizards is that increasing maximum temperatures have constrained lizard activity time in the breeding season beyond extinction thresholds. Here we document a significant population decline and potential local extinction at the warm (northern) range margin of the tawny dragon, Ctenophorus decresii, a rock-dwelling lizard from the Flinders Ranges in semi-arid Australia. We developed and tested a biophysical model of tawny dragon thermoregulatory behaviour and drove the model with daily weather data for the period 1990-2009 across the Flinders Ranges. Our results indicate that potential annual activity time has likely increased over this period throughout the historic range, with within-season declines only in the summer months at the northern range limit. However, populations that have declined since 2000 have also likely experienced higher active body temperatures and more stringent retreat-site requirements (deeper crevices) than have regions where the species remains common, during a period of declining rainfall. Our laboratory estimates of thermal preference in this species were insensitive to altered nutritional and hydric state. Thus it is possible that recent population declines are linked to desiccation stress driven by higher body temperatures and declining rainfall. Our study illustrates that simple indices of the impact of climate warming on animals, such as activity restriction, may in fact reflect a variety of potential mechanisms whose ultimate outcome will be contingent on other factors such as water and shelter availability. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cranial Radiation Therapy and Damage to Hippocampal Neurogenesis

ERIC Educational Resources Information Center

Monje, Michelle

2008-01-01

Cranial radiation therapy is associated with a progressive decline in cognitive function, prominently memory function. Impairment of hippocampal neurogenesis is thought to be an important mechanism underlying this cognitive decline. Recent work has elucidated the mechanisms of radiation-induced failure of neurogenesis. Potential therapeutic…

Reversible Deformation of Transfusion Tracheids in Taxus baccata Is Associated with a Reversible Decrease in Leaf Hydraulic Conductance1[OPEN

PubMed Central

Zhang, Yong-Jiang; Rockwell, Fulton E.; Wheeler, James K.; Holbrook, N. Michele

2014-01-01

Declines in leaf hydraulic conductance (Kleaf) with increasing water stress have been attributed to cavitation of the leaf xylem. However, in the leaves of conifers, the reversible collapse of transfusion tracheids may provide an alternative explanation. Using Taxus baccata, a conifer species without resin, we developed a modified rehydration technique that allows the separation of declines in Kleaf into two components: one reversible and one irreversible upon relaxation of water potential to −1 MPa. We surveyed leaves at a range of water potentials for evidence of cavitation using cryo-scanning electron microscopy and quantified dehydration-induced structural changes in transfusion tracheids by cryo-fluorescence microscopy. Irreversible declines in Kleaf did not occur until leaf water potentials were more negative than −3 MPa. Declines in Kleaf between −2 and −3 MPa were reversible and accompanied by the collapse of transfusion tracheids, as evidenced by cryo-fluorescence microscopy. Based on cryo-scanning electron microscopy, cavitation of either transfusion or xylem tracheids did not contribute to declines in Kleaf in the reversible range. Moreover, the deformation of transfusion tracheids was quickly reversible, thus acting as a circuit breaker regulating the flux of water through the leaf vasculature. As transfusion tissue is present in all gymnosperms, the reversible collapse of transfusion tracheids may be a general mechanism in this group for the protection of leaf xylem from excessive loads generated in the living leaf tissue. PMID:24948828

Cleaning at Home and at Work in Relation to Lung Function Decline and Airway Obstruction.

PubMed

Svanes, Øistein; Bertelsen, Randi J; Lygre, Stein H L; Carsin, Anne E; Antó, Josep M; Forsberg, Bertil; García-García, José M; Gullón, José A; Heinrich, Joachim; Holm, Mathias; Kogevinas, Manolis; Urrutia, Isabel; Leynaert, Bénédicte; Moratalla, Jesús M; Le Moual, Nicole; Lytras, Theodore; Norbäck, Dan; Nowak, Dennis; Olivieri, Mario; Pin, Isabelle; Probst-Hensch, Nicole; Schlünssen, Vivi; Sigsgaard, Torben; Skorge, Trude D; Villani, Simona; Jarvis, Debbie; Zock, Jan P; Svanes, Cecilie

2018-05-01

Cleaning tasks may imply exposure to chemical agents with potential harmful effects to the respiratory system, and increased risk of asthma and respiratory symptoms among professional cleaners and in persons cleaning at home has been reported. Long-term consequences of cleaning agents on respiratory health are, however, not well described. This study aimed to investigate long-term effects of occupational cleaning and cleaning at home on lung function decline and airway obstruction. The European Community Respiratory Health Survey (ECRHS) investigated a multicenter population-based cohort at three time points over 20 years. A total of 6,235 participants with at least one lung function measurement from 22 study centers, who in ECRHS II responded to questionnaire modules concerning cleaning activities between ECRHS I and ECRHS II, were included. The data were analyzed with mixed linear models adjusting for potential confounders. As compared with women not engaged in cleaning (ΔFEV 1  = -18.5 ml/yr), FEV 1 declined more rapidly in women responsible for cleaning at home (-22.1; P = 0.01) and occupational cleaners (-22.4; P = 0.03). The same was found for decline in FVC (ΔFVC = -8.8 ml/yr; -13.1, P = 0.02; and -15.9, P = 0.002; respectively). Both cleaning sprays and other cleaning agents were associated with accelerated FEV 1 decline (-22.0, P = 0.04; and -22.9, P = 0.004; respectively). Cleaning was not significantly associated with lung function decline in men or with FEV 1 /FVC decline or airway obstruction. Women cleaning at home or working as occupational cleaners had accelerated decline in lung function, suggesting that exposures related to cleaning activities may constitute a risk to long-term respiratory health.

Interactions of Hylastes Species (Coleoptera: Scolytidae) with Leptographium Species Associated with Loblolly Pine Decline

Treesearch

Lori G. Eckhardt; Richard A. Goyer; Kier Klepzig; John P. Jones

2004-01-01

Abstract Hylastes spp. (Coleoptera: Scolytidae)were evaluated as potential vectors of Leptographium spp. fungi. Bark beetles were trapped from stands of loblolly pine, Pinus taeda L., exhibiting a range of decline symptoms in central Alabama. Under controlled conditions, field-collected adult...

No Blue Ribbon

ERIC Educational Resources Information Center

Wilsey, Matthew; Kloser, Matthew

2015-01-01

Imagine middle and high school science classes without a science fair. Participation in science fairs is declining (Harmon 2011), a trend that some teachers, parents, and students find disturbing. The authors opine that the decline in science fairs calls for critically reviewing the potential disconnect between the aims and outcomes of science…

Nitrate Reductase Activity and Polyribosomal Content of Corn (Zea mays L.) Having Low Leaf Water Potentials 1

PubMed Central

Morilla, Camila A.; Boyer, J. S.; Hageman, R. H.

1973-01-01

Desiccation of 8- to 13-day-old seedlings, achieved by withholding nutrient solution from the vermiculite root medium, caused a reduction in nitrate reductase activity of the leaf tissue. Activity declined when leaf water potentials decreased below −2 bars and was 25% of the control at a leaf water potential of −13 bars. Experiments were conducted to determine whether the decrease in nitrate reductase activity was due to reduced levels of nitrate in the tissue, direct inactivation of the enzyme by low leaf water potentials, or to changes in rates of synthesis or decay of the enzyme. Although tissue nitrate content decreased with the onset of desiccation, it did not continue to decline with tissue desiccation and loss of enzyme activity. Nitrate reductase activity recovered when the plants were rewatered with nitrate-free medium, suggesting that the nitrate in the plant was adequate for high nitrate reductase activity. The rate of decay of nitrate reductase activity from desiccated tissue was essentially identical to that of the control, in vivo or in vitro, regardless of the rapidity of desiccation of the tissue. Direct inactivation of the enzyme by the low water potentials was not detected. Polyribosomal content of the tissue declined with the decrease in water potential, prior to the decline in nitrate reductase activity. Changes in ribosomal profiles occurred during desiccation, regardless of whether the tissue had been excised or not and whether desiccation was rapid or slow. Reduction in polyribosomal content did not appear to be associated with changes in ribonuclease activity. Nitrate reductase activity and the polyribosomal content of the tissue recovered upon rewatering, following the recovery in water potential. The increase in polyribosomal content preceded the increase in nitrate reductase activity. Recovery of enzyme activity was prevented by cycloheximide. Based on these results, it appears that nitrate reductase activity was affected primarily by a decrease in the rate of enzyme synthesis at low leaf water potentials. PMID:16658419

Longitudinal cognitive biomarkers predicting symptom onset in presymptomatic frontotemporal dementia.

PubMed

Jiskoot, Lize C; Panman, Jessica L; van Asseldonk, Lauren; Franzen, Sanne; Meeter, Lieke H H; Donker Kaat, Laura; van der Ende, Emma L; Dopper, Elise G P; Timman, Reinier; van Minkelen, Rick; van Swieten, John C; van den Berg, Esther; Papma, Janne M

2018-06-01

We performed 4-year follow-up neuropsychological assessment to investigate cognitive decline and the prognostic abilities from presymptomatic to symptomatic familial frontotemporal dementia (FTD). Presymptomatic MAPT (n = 15) and GRN mutation carriers (n = 31), and healthy controls (n = 39) underwent neuropsychological assessment every 2 years. Eight mutation carriers (5 MAPT, 3 GRN) became symptomatic. We investigated cognitive decline with multilevel regression modeling; the prognostic performance was assessed with ROC analyses and stepwise logistic regression. MAPT converters declined on language, attention, executive function, social cognition, and memory, and GRN converters declined on attention and executive function (p < 0.05). Cognitive decline in ScreeLing phonology (p = 0.046) and letter fluency (p = 0.046) were predictive for conversion to non-fluent variant PPA, and decline on categorical fluency (p = 0.025) for an underlying MAPT mutation. Using longitudinal neuropsychological assessment, we detected a mutation-specific pattern of cognitive decline, potentially suggesting prognostic value of neuropsychological trajectories in conversion to symptomatic FTD.

Soil acidity and manganese in declining and nondeclining sugar maple stands in Pennsylvania.

PubMed

Kogelmann, Wilhelm J; Sharpe, William E

2006-01-01

For decades, the hardwood forests of northern Pennsylvania have been subjected to chronic atmospheric loading of acidifying agents. On marginal, high-elevation, unglaciated sites, sugar maples (Acer saccharum Marsh.) have experienced severe decline symptoms and mortality. Accelerated soil acidification, base cation leaching, and increased availability of toxic metals have been suggested as predisposing factors contributing to this decline. Manganese, an essential micronutrient, is also a potentially phytotoxic metal that may be a factor associated with poor sugar maple health on soils vulnerable to acidification from anthropogenic sources. We measured Mn levels in four compartments of the soil-tree system (soil, foliage, xylem wood, and sap) on three sugar maple stands in northern Pennsylvania. Two stands were classified as declining and one was in good health. Negative correlations were found between soil pH and Mn levels in the soil, foliage, sap, and xylem wood. Levels of Mn in these pools were consistently higher on declining sites, which correspondingly exhibited lower levels of Ca and Mg. Species differences between red maple (Acer rubrum L.) and sugar maple at the two declining sites suggested different tolerances to excessive Mn. Molar ratios of Mg/Mn and Ca/Mn were different among sites and showed potential as indicators of soil acidification. Significant correlations among soil, sap, foliage, and xylem wood Mn were also noted. These results show clear Mn differences among sites and, when viewed with recent Mn toxicity experiments and other observational studies, suggest that excessive Mn may play a role in the observed decline and mortality of sugar maple.

Mapping global potential risk of mango sudden decline disease caused by fungus Ceratocystis fimbriata

USDA-ARS?s Scientific Manuscript database

Mango Sudden Decline (MSD), sometimes referred to as mango wilt, is an important disease of mango caused by one of the most significant fungal species causing disease in woody plants, Ceratocystis fimbriata. This species is mainly disseminated by the mango bark beetle, Hypocryphalus mangiferae (Steb...

Key environmental determinants of global and regional richness patterns for a wild bee subfamily

USDA-ARS?s Scientific Manuscript database

Reports of world-wide decline of pollinators, and of bees in particular, raise increasing concerns about food security. While local factors of bee decline are relatively well known and potential mitigation strategies on landscape scale have been outlined, the regional and continental-scale threats t...

Competitive actions of small firms in a declining market

Treesearch

Matthew Bumgardner; Urs Buehlmann; Albert Schuler; Jeff Crissey

2011-01-01

Small firms, through their flexibility advantages and closeness to customers, potentially can increase their sales volume in economic downturns. The decline in U.S. housing construction (beginning in 2006) provided an opportunity to develop and test four hypotheses predicting the attributes and marketing actions associated with successful companies supplying housing...

Predation of Karluk River sockeye salmon by coho salmon and char

USGS Publications Warehouse

McIntyre, J.D.; Reisenbichler, R.R.; Emlen, J.M.; Wilmot, R.L.; Finn, J.E.

1988-01-01

The number of sockeye salmon, Oncorhynchus nerka, in Alaska's Karluk River (Fig. 1) declined from millions to thousands during the early part of the present century. Rounsefell (1958) discussed alternative explanations for the decline including a general loss offertility ofthe system as the number of salmon carcasses declined, competition, overfishing, subtle changes in climate, and predation; he concluded that the combined effect of predation and fishing was the most probable explanation. Later, Van Cleave and Bevan (1973) suggested that the weir constructed in the river each year to facilitate counting the fish as they entered the system was the most probable cause ofthe decline. Itprevented free movement of both adults and juveniles in the river. All of these hypotheses remain as potential explanations for the decline

Risk Factors for Rapid Kidney Function Decline Among African Americans: The Jackson Heart Study (JHS)

PubMed Central

Young, Bessie A.; Katz, Ronit; Boulware, Ebony; Kestenbaum, Bryan; de Boer, Ian H.; Wang, Wei; Fülöp, Tibor; Bansal, Nisha; Robinson-Cohen, Cassianne; Griswold, Michael; Powe, Neil N.; Himmelfarb, Jonathan; Correa, Adolfo

2016-01-01

Background Racial differences in rapid kidney function decline exist, but less is known regarding factors associated with rapid decline among African Americans. A greater understanding of potentially modifiable risk factors for early kidney function loss may help reduce the burden of kidney failure in this high-risk population. Study Design Prospective cohort study. Setting & Participants 3653 African-American participants enrolled in the Jackson Heart Study (JHS) with kidney function data from two of three examinations (2000-2004 and 2009-2013). Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine using the CKD-EPI creatinine equation. Predictors Demographics, socioeconomic status, lifestyle, clinical risk factors for kidney failure. Outcomes Rapid decline was defined as a ≥ 30% decline in eGFR during follow-up. We quantified the association of risk factors with rapid decline in multivariable models. Measurements Clinical (systolic blood pressure, albuminuria [albumin-creatinine ratio]) and modifiable risk factors. Results Mean age was 54 ± 12 (SD) years, 37% were male, average body mass index was 31.8 ± 7.1 kg/m2, 19% had diabetes mellitus (DM) and mean eGFR was 96.0 ±20 ml/min/1.73m2 with an annual rate of decline of 1.27 ml/min/1.73m2. Those with rapid decline (11.5%) were older, more likely to be of low/middle income, had higher systolic blood pressure, and greater DM than those with non-rapid decline. Factors associated with ≥30% decline were older age (adjusted OR per 10 years older, 1.51; 95% CI, 1.34-1.71); cardiovascular disease (adjusted OR, 1.53; 95% CI, 1.12-2.10), higher systolic blood pressure (adjusted OR per 17 mm Hg greater, 1.22; 95% CI, 1.06-1.41); DM (adjusted OR, 2.63; 95% CI, 2.02-3.41), smoking (adjusted OR, 1.60; 95% CI, 1.10-2.31), and albumin-creatinine ratio > 30 mg/g (adjusted OR, 1.55; 95% CI, 1.08-1.21). Conversely, results did not support associations of waist circumference, C-reactive protein, and physical activity with rapid decline. Limitations No mid study creatinine measurement at examination 2 (2005-2008). Conclusions Rapid decline heterogeneity existed among African Americans in JHS. Interventions targeting potentially modifiable factors may help reduce the incidence of kidney failure. PMID:27066930

Risk Factors for Rapid Kidney Function Decline Among African Americans: The Jackson Heart Study (JHS).

PubMed

Young, Bessie A; Katz, Ronit; Boulware, L Ebony; Kestenbaum, Bryan; de Boer, Ian H; Wang, Wei; Fülöp, Tibor; Bansal, Nisha; Robinson-Cohen, Cassianne; Griswold, Michael; Powe, Neil R; Himmelfarb, Jonathan; Correa, Adolfo

2016-08-01

Racial differences in rapid kidney function decline exist, but less is known regarding factors associated with rapid decline among African Americans. Greater understanding of potentially modifiable risk factors for early kidney function loss may help reduce the burden of kidney failure in this high-risk population. Prospective cohort study. 3,653 African American participants enrolled in the Jackson Heart Study (JHS) with kidney function data from 2 of 3 examinations (2000-2004 and 2009-2013). Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine using the CKD-EPI creatinine equation. Demographics, socioeconomic status, lifestyle, and clinical risk factors for kidney failure. Rapid decline was defined as a ≥30% decline in eGFR during follow-up. We quantified the association of risk factors with rapid decline in multivariable models. Clinical (systolic blood pressure and albuminuria [albumin-creatinine ratio]) and modifiable risk factors. Mean age was 54±12 (SD) years, 37% were men, average body mass index was 31.8±7.1kg/m(2), 19% had diabetes mellitus (DM), and mean eGFR was 96.0±20mL/min/1.73m(2) with an annual rate of decline of 1.27mL/min/1.73m(2). Those with rapid decline (11.5%) were older, were more likely to be of low/middle income, and had higher systolic blood pressures and greater DM than those with nonrapid decline. Factors associated with ≥30% decline were older age (adjusted OR per 10 years older, 1.51; 95% CI, 1.34-1.71), cardiovascular disease (adjusted OR, 1.53; 95% CI, 1.12-2.10), higher systolic blood pressure (adjusted OR per 17mmHg greater, 1.22; 95% CI, 1.06-1.41), DM (adjusted OR, 2.63; 95% CI, 2.02-3.41), smoking (adjusted OR, 1.60; 95% CI, 1.10-2.31), and albumin-creatinine ratio > 30mg/g (adjusted OR, 1.55; 95% CI, 1.08-1.21). Conversely, results did not support associations of waist circumference, C-reactive protein level, and physical activity with rapid decline. No midstudy creatinine measurement at examination 2 (2005-2008). Rapid decline heterogeneity exists among African Americans in JHS. Interventions targeting potentially modifiable factors may help reduce the incidence of kidney failure. Published by Elsevier Inc.

Telling a (good?) counterstory of aging: natural bodybuilding meets the narrative of decline.

PubMed

Phoenix, Cassandra; Smith, Brett

2011-09-01

In Western society, the narrative of decline dominates the aging process. We know very little about the complexities of how people resist this narrative. The purpose of this article is to understand how a group of mature natural bodybuilders resisted the narrative of decline. In-depth life story interviews were conducted with 13 natural bodybuilders aged between 50 and 73 years. Verbatim transcripts were produced and the data analyzed using a structural narrative analysis. A dialogical analysis was also utilized. The participants' experiences did not fit with stereotypical assumptions about decline and deterioration in older age. They all told counterstories to "natural" aging, yet what differed was how the participants' counterstories resisted the narrative of decline and the level of resistance that they provided. We advance knowledge in the fields of aging and narrative inquiry by revealing the multidimensionality of resistance. We demonstrated how participants storied resistance in different ways and the important implications this had for the way aging was understood and acted upon-by themselves and potentially by others. In addition to advancing theoretical knowledge, in this article, we also significantly contribute to understandings of the potential of narrative for changing human lives and behavior across the life course in more positive and nuanced ways.

Life Cycles, Educational Attainment and Labor Markets.

ERIC Educational Resources Information Center

Winsborough, H.H., Sweet, J.A.

Two social changes are cited as particularly important to the projection of college enrollment trends. One is the rising educational attainment of the parents of future potential college attenders; the other is the fact that declines in fertility accompany declines in average family size. Overall, the illustration in this paper suggests that the…

Changes in High School Vocational Coursetaking in a Larger Perspective. Stats in Brief.

ERIC Educational Resources Information Center

Hurst, David; Hudson, Lisa

The decline in vocational coursetaking from 1982-1998 is relatively small compared to increases in academic coursetaking. The potential trade-off between academic and vocational coursetaking seems to have been mitigated by students taking more courses overall and fewer courses in the general curriculum. Further, the decline in vocational…

Devastating decline of forest elephants in central Africa.

PubMed

Maisels, Fiona; Strindberg, Samantha; Blake, Stephen; Wittemyer, George; Hart, John; Williamson, Elizabeth A; Aba'a, Rostand; Abitsi, Gaspard; Ambahe, Ruffin D; Amsini, Fidèl; Bakabana, Parfait C; Hicks, Thurston Cleveland; Bayogo, Rosine E; Bechem, Martha; Beyers, Rene L; Bezangoye, Anicet N; Boundja, Patrick; Bout, Nicolas; Akou, Marc Ella; Bene, Lambert Bene; Fosso, Bernard; Greengrass, Elizabeth; Grossmann, Falk; Ikamba-Nkulu, Clement; Ilambu, Omari; Inogwabini, Bila-Isia; Iyenguet, Fortune; Kiminou, Franck; Kokangoye, Max; Kujirakwinja, Deo; Latour, Stephanie; Liengola, Innocent; Mackaya, Quevain; Madidi, Jacob; Madzoke, Bola; Makoumbou, Calixte; Malanda, Guy-Aimé; Malonga, Richard; Mbani, Olivier; Mbendzo, Valentin A; Ambassa, Edgar; Ekinde, Albert; Mihindou, Yves; Morgan, Bethan J; Motsaba, Prosper; Moukala, Gabin; Mounguengui, Anselme; Mowawa, Brice S; Ndzai, Christian; Nixon, Stuart; Nkumu, Pele; Nzolani, Fabian; Pintea, Lilian; Plumptre, Andrew; Rainey, Hugo; de Semboli, Bruno Bokoto; Serckx, Adeline; Stokes, Emma; Turkalo, Andrea; Vanleeuwe, Hilde; Vosper, Ashley; Warren, Ymke

2013-01-01

African forest elephants- taxonomically and functionally unique-are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002-2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced.

Age-related decline in cognitive control: the role of fluid intelligence and processing speed

PubMed Central

2014-01-01

Background Research on cognitive control suggests an age-related decline in proactive control abilities whereas reactive control seems to remain intact. However, the reason of the differential age effect on cognitive control efficiency is still unclear. This study investigated the potential influence of fluid intelligence and processing speed on the selective age-related decline in proactive control. Eighty young and 80 healthy older adults were included in this study. The participants were submitted to a working memory recognition paradigm, assessing proactive and reactive cognitive control by manipulating the interference level across items. Results Repeated measures ANOVAs and hierarchical linear regressions indicated that the ability to appropriately use cognitive control processes during aging seems to be at least partially affected by the amount of available cognitive resources (assessed by fluid intelligence and processing speed abilities). Conclusions This study highlights the potential role of cognitive resources on the selective age-related decline in proactive control, suggesting the importance of a more exhaustive approach considering the confounding variables during cognitive control assessment. PMID:24401034

The dependence of the action potential of the frog's heart on the external and intracellular sodium concentration

PubMed Central

Niedergerke, R.; Orkand, R. K.

1966-01-01

1. The overshoot of the action potential of the frog's heart was reduced when external sodium chloride was replaced by sucrose. However, the potential decrement was only 17·3 mV for a 10-fold reduction of sodium as compared with 58 mV expected on the basis of the sodium hypothesis of excitation. 2. Replacement of up to 75% of the external sodium by choline did not reduce the overshoot, provided atropine was present in sufficient concentrations to suppress any parasympathomimetic action. 3. The maximum rate of rise of the action potential markedly declined in low sodium fluids whether sucrose or choline chloride was used to replace sodium chloride. 4. The maximum rate of rise was reduced to only a small extent when external sodium was replaced by lithium. 5. Increasing the intracellular sodium concentration in exchange for lost potassium caused overshoots to decline. The effects resembled those obtained in similar experiments with skeletal muscle fibres (Desmedt, 1953). 6. Action potentials occurring under certain conditions even in the presence of very low external sodium concentrations (≤ 5% normal) also declined in height when the intracellular sodium concentration was increased. 7. The behaviour of the action potential in low external sodium concentrations may be explained by an action of calcium on the excitable membrane. PMID:5921833

Biophysical basis of growth promotion in primary leaves of Phaseolus vulgaris L. by hormones versus light: solute accumulation and the growth potential

NASA Technical Reports Server (NTRS)

Brock, T. G.; Cleland, R. E.

1990-01-01

Rapid cell enlargement in primary leaves of bean is induced by bright white light (WL), gibberellic acid (GA3) or the cytokinin N6-benzyladenine (BA). In previous studies it has been show that all three agents cause an increase in wall extensibility, although by different mechanisms. Here we examine the effects of the three growth promoters on the osmotic potential difference (delta Psi), the accumulation of solutes (delta TSC), the wall yield threshold (Y) and the growth potential (delta Psi -Y). With GA3 and BA, but not WL, there was a rapid decline in delta Psi as measured by the osmotic concentration of expressed sap. Unlike WL, neither GA3 nor BA promoted the accumulation of osmotic solutes. The decline in delta Psi, however, was apparently counteracted by a decline in Y since the growth potential, as measured by the external-osmoticum method, remained unchanged. It is concluded that WL, GA3 and BA all promote cell enlargement of bean leaves by increasing one cellular growth parameter, wall extensibility. Only WL, however, promotes osmotic adjustment during growth.

Gait dyspraxia as a clinical marker of cognitive decline in Down syndrome: A review of theory and proposed mechanisms.

PubMed

Anderson-Mooney, Amelia J; Schmitt, Frederick A; Head, Elizabeth; Lott, Ira T; Heilman, Kenneth M

2016-04-01

Down syndrome (DS) is the most common genetic cause of intellectual disability in children. With aging, DS is associated with an increased risk for Alzheimer's disease (AD). The development of AD neuropathology in individuals with DS can result in further disturbances in cognition and behavior and may significantly exacerbate caregiver burden. Early detection may allow for appropriate preparation by caregivers. Recent literature suggests that declines in gait may serve as an early marker of AD-related cognitive disorders; however, this relationship has not been examined in individuals with DS. The theory regarding gait dyspraxia and cognitive decline in the general population is reviewed, and potential applications to the population with individuals with DS are highlighted. Challenges and benefits in the line of inquiry are discussed. In particular, it appears that gait declines in aging individuals with DS may be associated with known declines in frontoparietal gray matter, development of AD-related pathology, and white matter losses in tracts critical to motor control. These changes are also potentially related to the cognitive and functional changes often observed during the same chronological period as gait declines in adults with DS. Gait declines may be an early marker of cognitive change, related to the development of underlying AD-related pathology, in individuals with DS. Future investigations in this area may provide insight into the clinical changes associated with development of AD pathology in both the population with DS and the general population, enhancing efforts for optimal patient and caregiver support and propelling investigations regarding safety/quality of life interventions and disease-modifying interventions. Copyright © 2016 Elsevier Inc. All rights reserved.

The cause of global amphibian declines: a developmental endocrinologist's perspective.

PubMed

Hayes, T B; Falso, P; Gallipeau, S; Stice, M

2010-03-15

Greater than 70% of the world's amphibian species are in decline. We propose that there is probably not a single cause for global amphibian declines and present a three-tiered hierarchical approach that addresses interactions among and between ultimate and proximate factors that contribute to amphibian declines. There are two immediate (proximate) causes of amphibian declines: death and decreased recruitment (reproductive failure). Although much attention has focused on death, few studies have addressed factors that contribute to declines as a result of failed recruitment. Further, a great deal of attention has focused on the role of pathogens in inducing diseases that cause death, but we suggest that pathogen success is profoundly affected by four other ultimate factors: atmospheric change, environmental pollutants, habitat modification and invasive species. Environmental pollutants arise as likely important factors in amphibian declines because they have realized potential to affect recruitment. Further, many studies have documented immunosuppressive effects of pesticides, suggesting a role for environmental contaminants in increased pathogen virulence and disease rates. Increased attention to recruitment and ultimate factors that interact with pathogens is important in addressing this global crisis.

The cause of global amphibian declines: a developmental endocrinologist's perspective

PubMed Central

Hayes, T. B.; Falso, P.; Gallipeau, S.; Stice, M.

2010-01-01

Greater than 70% of the world's amphibian species are in decline. We propose that there is probably not a single cause for global amphibian declines and present a three-tiered hierarchical approach that addresses interactions among and between ultimate and proximate factors that contribute to amphibian declines. There are two immediate (proximate) causes of amphibian declines: death and decreased recruitment (reproductive failure). Although much attention has focused on death, few studies have addressed factors that contribute to declines as a result of failed recruitment. Further, a great deal of attention has focused on the role of pathogens in inducing diseases that cause death, but we suggest that pathogen success is profoundly affected by four other ultimate factors: atmospheric change, environmental pollutants, habitat modification and invasive species. Environmental pollutants arise as likely important factors in amphibian declines because they have realized potential to affect recruitment. Further, many studies have documented immunosuppressive effects of pesticides, suggesting a role for environmental contaminants in increased pathogen virulence and disease rates. Increased attention to recruitment and ultimate factors that interact with pathogens is important in addressing this global crisis. PMID:20190117

Hypertension is associated with cognitive decline in elderly people at high risk for dementia.

PubMed

Wysocki, Michael; Luo, Xiaodong; Schmeidler, James; Dahlman, Karen; Lesser, Gerson T; Grossman, Hillel; Haroutunian, Vahram; Beeri, Michal Schnaider

2012-02-01

Cardiovascular risk factors including hypertension (HTN) have been shown to increase the risk of Alzheimer disease. The current study investigated whether individuals with HTN are more susceptible to increased cognitive decline and whether the influence of HTN on cognitive decline varied as a function of dementia severity. A total of 224 nursing home and assisted living residents, with a mean age of 84.9 (±7.6) years, were assessed longitudinally with Mini Mental State Exams (MMSEs) and Clinical Dementia Ratings (CDR). Baseline dementia status was defined by the CDR score. As described in , MMSE scores in persons with HTN and questionable dementia (CDR = 0.5) declined significantly faster than nonhypertensive questionably demented persons. Hypertensive participants did not decline significantly faster than nonhypertensive participants in persons with intact cognition (CDR = 0) or frank dementia (CDR ≥ 1). These results suggest an increased risk of subsequent cognitive decline in hypertensive individuals who are especially vulnerable to developing dementia and raises the possibility that avoiding or controlling HTN might reduce the rate of cognitive decline in cognitively vulnerable individuals, potentially delaying their conversion to full-fledged dementia.

Change in physical mobility over 10 years in post-polio syndrome.

PubMed

Bickerstaffe, A; Beelen, A; Nollet, F

2015-03-01

Post-polio syndrome is characterised by progressive muscle weakness and other symptoms which can limit physical mobility. We assessed the rate of decline in mobility over 10 years in relation to strength decline; and investigated potential predictors for the rate of decline of walking capacity, a measure of mobility, in 48 patients with post-polio syndrome and proven quadriceps dysfunction at baseline. Average walking capacity and self-reported physical mobility declined over 10 years, by 6 and 14%, respectively. Concomitantly people lost an average of 15% of isometric quadriceps strength. Significantly more people used walking aids offering greater support at follow-up. Notably, there was much individual variation, with 18% of participants losing a substantial amount of walking capacity (27% decline) and concomitant self-reported physical mobility (38% decline). Loss of quadriceps strength only explained a small proportion of the variance of the decline in walking capacity (R = 11%) and the rate of decline could not be predicted from baseline values for strength, walking capacity, self-reported physical mobility or basic demographics. The individual variability, yet lack of predictive factors, underscores the need for personally tailored care based on actual functional decline in patients with post-polio syndrome. Copyright © 2014. Published by Elsevier B.V.

Leaf hydraulic conductance, measured in situ, declines and recovers daily: leaf hydraulics, water potential and stomatal conductance in four temperate and three tropical tree species.

PubMed

Johnson, D M; Woodruff, D R; McCulloh, K A; Meinzer, F C

2009-07-01

Adequate leaf hydraulic conductance (Kleaf) is critical for preventing transpiration-induced desiccation and subsequent stomatal closure that would restrict carbon gain. A few studies have reported midday depression of Kleaf (or petiole conductivity) and its subsequent recovery in situ, but the extent to which this phenomenon is universal is not known. The objectives of this study were to measure Kleaf, using a rehydration kinetics method, (1) in the laboratory (under controlled conditions) across a range of water potentials to construct vulnerability curves (VC) and (2) over the course of the day in the field along with leaf water potential and stomatal conductance (gs). Two broadleaf (one evergreen, Arbutus menziesii Pursh., and one deciduous, Quercus garryana Dougl.) and two coniferous species (Pinus ponderosa Dougl. and Pseudotsuga menziesii [Mirbel]) were chosen as representative of different plant types. In addition, Kleaf in the laboratory and leaf water potential in the field were measured for three tropical evergreen species (Protium panamense (Rose), Tachigalia versicolor Standley and L.O. Williams and Vochysia ferruginea Mart) to predict their daily changes in field Kleaf in situ. It was hypothesized that in the field, leaves would close their stomata at water potential thresholds at which Kleaf begins to decline sharply in laboratory-generated VC, thus preventing substantial losses of Kleaf. The temperate species showed a 15-66% decline in Kleaf by midday, before stomatal closure. Although there were substantial midday declines in Kleaf, recovery was nearly complete by late afternoon. Stomatal conductance began to decrease in Pseudotsuga, Pinus and Quercus once Kleaf began to decline; however, there was no detectable reduction in gs in Arbutus. Predicted Kleaf in the tropical species, based on laboratory-generated VC, decreased by 74% of maximum Kleaf in Tachigalia, but only 22-32% in Vochysia and Protium. The results presented here, from the previous work of the authors and from other published studies, were consistent with two different strategies regarding daily maintenance of Kleaf: (1) substantial loss and subsequent recovery or (2) a more conservative strategy of loss avoidance.

An Investigation of the Hydroclimate Variability of Eastern Africa

NASA Astrophysics Data System (ADS)

Smith, K. A.; Semazzi, F. H. M.

2015-12-01

The flow of the Victoria Nile, and the productivity of the dams along it, is determined by the level of Lake Victoria, which is primarily dictated by the rainfall and temperature variability over the Lake Victoria Basin. Notwithstanding the indisputable decline of water resources over the lake basin during the Long Rains of March - May, there is a strong indication based on IPCC climate projections that this trend, which has persisted for several decades, will reverse in the next few decades. This phenomenon has come to be known as the Eastern-Central African climate change paradox and could have profound implications on sustainable development for the next few decades in Lake Victoria Basin. The purpose of this study is to investigate the climate variability associated with the East African Climate Change Paradox for the recent decades. This research analyzes observations to understand the sources of variability and potential physical mechanisms related to the decline in precipitation over Eastern Africa. We then investigate the hydrological factors involved in the decline of Lake Victoria levels in the context of the decline in rainfall. While East Africa has been experiencing persistent decline of the Long Rains for multiple decades, this same decline is not seen in annual rainfall. The remaining seasons show an increase in rainfall which is compensating for the decline of the Long Rains. It is possible that the Long Rains season is shifting in such a way that the season starts earlier, in February, and ending sooner. The corresponding annual Lake Victoria levels modeled using observed rainfall do not decline in the recent decades, except when the Long Rains seasonal variability is considered without variability from other seasons. This shift could impact hydroelectric power planning on a monthly or seasonal time scale, and could potentially have a large impact on agriculture, since it would shift the growing season in the region.

Feeding preference of the Rio Grande silvery minnow (Hybognathus amarus)

Treesearch

Hugo A. Magana

2009-01-01

The Rio Grande silvery minnow (Hybognathus amarus) was historically the most abundant fish in the Rio Grande Basin. However, populations have been declining to the point of being listed under the Endangered Species Act. Potential causes for the decline have been studied, yet little attention has been paid to food resources. This study had three...

Potential streamflow changes from forest decline due to air pollution

Treesearch

R. M. Rice; J. Lewis

1988-01-01

In recent years, serious die-back of forest trees has been reported in western Europe and eastern North America. One presumed cause of the forest decline is air pollution and acid deposition. Concern has been expressed that adverse hydrologic responses might occur in forested watersheds as the result of reduced evapotranspiration and increased discharge. According...

Examining the Potential of Information Technologies to Improve Cost Control in Community Colleges

ERIC Educational Resources Information Center

Sudhakar, Samuel

2013-01-01

The challenges facing publicly funded community colleges have never been greater. Declining state and federal support and decreasing property tax revenues have placed a tremendous pressure on tuition rates. Declining revenues combined with the lack of adequate cost control, has caused in-state tuition and fees at public 2-year colleges to increase…

Professional and Geographic Mobility of a Selected Sample of Nebraska Public School Administrators: Differences between Men and Women.

ERIC Educational Resources Information Center

Truett, Carol

Women have comprised a declining percentage of public school administrators since 1928 when 55 percent of all elementary principals were female. A heretofore unchallenged reason for this decline has been the assumption that women lack geographic mobility and that consequently neither they themselves nor potential employers should consider them…

An evaluation of powerline rights-of-way as habitat for early-successional shrubland birds

Treesearch

David I. King; Bruce E. Byers

2002-01-01

Recent population declines among bird species that breed in early-successional shrubland habitats in the eastern United States have been associated with declines in habitat availability. Forest succession has eliminated shrublands in many locations, but powerline rights-of-way constitute a potential reservoir of shrubland habitat for birds. We studied 2 populations of...

Hypertension and vascular dementia in the elderly: the potential role of anti-hypertensive agents.

PubMed

Coca, Antonio

2013-09-01

Vascular dementia (VaD) - a severe form of vascular cognitive impairment - and cognitive decline are associated with hypertension and therefore it seems logical to consider that reducing BP with anti-hypertensive therapy may protect against the development/onset of cognitive function impairment or dementia. This narrative, non-systematic review discusses the available evidence on the potential correlation between the use of anti-hypertensive agents and the risk of VaD and cognitive decline. MEDLINE was searched for inclusion of relevant studies. No limitations in time were considered. A consensus on the potential effects of anti-hypertensive treatment in the reduction of VaD and associated cognitive decline has not been reached. A protective effect of anti-hypertensive agents has been observed in a number of studies although it is still unclear whether different classes of anti-hypertensive agents have a different effect on the development of VaD. The protective effect of anti-hypertensive agents appears to depend on the specific drug used - positive effects have been observed with calcium channel blockers (CCBs), such as lercanidipine and nitrendipine, the combination perindopril-indapamide and telmisartan.

A Hydraulic Model Is Compatible with Rapid Changes in Leaf Elongation under Fluctuating Evaporative Demand and Soil Water Status1[C][W][OPEN

PubMed Central

Caldeira, Cecilio F.; Bosio, Mickael; Parent, Boris; Jeanguenin, Linda; Chaumont, François; Tardieu, François

2014-01-01

Plants are constantly facing rapid changes in evaporative demand and soil water content, which affect their water status and growth. In apparent contradiction to a hydraulic hypothesis, leaf elongation rate (LER) declined in the morning and recovered upon soil rehydration considerably quicker than transpiration rate and leaf water potential (typical half-times of 30 min versus 1–2 h). The morning decline of LER began at very low light and transpiration and closely followed the stomatal opening of leaves receiving direct light, which represent a small fraction of leaf area. A simulation model in maize (Zea mays) suggests that these findings are still compatible with a hydraulic hypothesis. The small water flux linked to stomatal aperture would be sufficient to decrease water potentials of the xylem and growing tissues, thereby causing a rapid decline of simulated LER, while the simulated water potential of mature tissues declines more slowly due to a high hydraulic capacitance. The model also captured growth patterns in the evening or upon soil rehydration. Changes in plant hydraulic conductance partly counteracted those of transpiration. Root hydraulic conductivity increased continuously in the morning, consistent with the transcript abundance of Zea maize Plasma Membrane Intrinsic Protein aquaporins. Transgenic lines underproducing abscisic acid, with lower hydraulic conductivity and higher stomatal conductance, had a LER declining more rapidly than wild-type plants. Whole-genome transcriptome and phosphoproteome analyses suggested that the hydraulic processes proposed here might be associated with other rapidly occurring mechanisms. Overall, the mechanisms and model presented here may be an essential component of drought tolerance in naturally fluctuating evaporative demand and soil moisture. PMID:24420931

Devastating Decline of Forest Elephants in Central Africa

PubMed Central

Blake, Stephen; Wittemyer, George; Hart, John; Williamson, Elizabeth A.; Aba’a, Rostand; Abitsi, Gaspard; Ambahe, Ruffin D.; Amsini, Fidèl; Bakabana, Parfait C.; Hicks, Thurston Cleveland; Bayogo, Rosine E.; Bechem, Martha; Beyers, Rene L.; Bezangoye, Anicet N.; Boundja, Patrick; Bout, Nicolas; Akou, Marc Ella; Bene, Lambert Bene; Fosso, Bernard; Greengrass, Elizabeth; Grossmann, Falk; Ikamba-Nkulu, Clement; Ilambu, Omari; Inogwabini, Bila-Isia; Iyenguet, Fortune; Kiminou, Franck; Kokangoye, Max; Kujirakwinja, Deo; Latour, Stephanie; Liengola, Innocent; Mackaya, Quevain; Madidi, Jacob; Madzoke, Bola; Makoumbou, Calixte; Malanda, Guy-Aimé; Malonga, Richard; Mbani, Olivier; Mbendzo, Valentin A.; Ambassa, Edgar; Ekinde, Albert; Mihindou, Yves; Morgan, Bethan J.; Motsaba, Prosper; Moukala, Gabin; Mounguengui, Anselme; Mowawa, Brice S.; Ndzai, Christian; Nixon, Stuart; Nkumu, Pele; Nzolani, Fabian; Pintea, Lilian; Plumptre, Andrew; Rainey, Hugo; de Semboli, Bruno Bokoto; Serckx, Adeline; Stokes, Emma; Turkalo, Andrea; Vanleeuwe, Hilde; Vosper, Ashley; Warren, Ymke

2013-01-01

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced. PMID:23469289

When can the cause of a population decline be determined?

PubMed

Hefley, Trevor J; Hooten, Mevin B; Drake, John M; Russell, Robin E; Walsh, Daniel P

2016-11-01

Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time. © 2016 John Wiley & Sons Ltd/CNRS.

When can the cause of a population decline be determined?

USGS Publications Warehouse

Hefley, Trevor J.; Hooten, Mevin B.; Drake, John M.; Russell, Robin E.; Walsh, Daniel P.

2016-01-01

Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time.

Accelerated cognitive decline in a rodent model for temporal lobe epilepsy.

PubMed

Schipper, Sandra; Aalbers, Marlien W; Rijkers, Kim; Lagiere, Melanie; Bogaarts, Jan G; Blokland, Arjan; Klinkenberg, Sylvia; Hoogland, Govert; Vles, Johan S H

2016-12-01

Cognitive impairment is frequently observed in patients with temporal lobe epilepsy. It is hypothesized that cumulative seizure exposure causes accelerated cognitive decline in patients with epilepsy. We investigated the influence of seizure frequency on cognitive decline in a rodent model for temporal lobe epilepsy. Neurobehavioral assessment was performed before and after surgery, after the induction of self-sustaining limbic status epilepticus (SSLSE), and in the chronic phase in which rats experienced recurrent seizures. Furthermore, we assessed potential confounders of memory performance. Rats showed a deficit in spatial working memory after the induction of the SSLSE, which endured in the chronic phase. A progressive decline in recognition memory developed in SSLSE rats. Confounding factors were absent. Seizure frequency and also the severity of the status epilepticus were not correlated with the severity of cognitive deficits. The effect of the seizure frequency on cognitive comorbidity in epilepsy has long been debated, possibly because of confounders such as antiepileptic medication and the heterogeneity of epileptic etiologies. In an animal model of temporal lobe epilepsy, we showed that a decrease in spatial working memory does not relate to the seizure frequency. This suggests for other mechanisms are responsible for memory decline and potentially a common pathophysiology of cognitive deterioration and the occurrence and development of epileptic seizures. Identifying this common denominator will allow development of more targeted interventions treating cognitive decline in patients with epilepsy. The treatment of interictal symptoms will increase the quality of life of many patients with epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

Contrasting olfaction, vision, and audition as predictors of cognitive change and impairment in non-demented older adults.

PubMed

MacDonald, Stuart W S; Keller, Connor J C; Brewster, Paul W H; Dixon, Roger A

2018-05-01

This study examines the relative utility of a particular class of noninvasive functional biomarkers-sensory functions-for detecting those at risk of cognitive decline and impairment. Three central research objectives were examined including whether (a) olfactory function, vision, and audition exhibited significant longitudinal declines in nondemented older adults; (b) multiwave change for these sensory function indicators predicted risk of mild cognitive impairment (MCI); and (c) change within persons for each sensory measure shared dynamic time-varying associations with within-person change in cognitive functioning. A longitudinal sample (n = 408) from the Victoria Longitudinal Study was assembled. Three cognitive status subgroups were identified: not impaired cognitively, single-assessment MCI, and multiple-assessment MCI. We tested independent predictive associations, contrasting change in sensory function as predictors of cognitive decline and impairment, utilizing both linear mixed models and logistic regression analysis. Olfaction and, to a lesser extent, vision were identified as the most robust predictors of cognitive status and decline; audition showed little predictive influence. These findings underscore the potential utility of deficits in olfactory function, in particular, as an early marker of age- and pathology-related cognitive decline. Functional biomarkers may represent potential candidates for use in the early stages of a multistep screening approach for detecting those at risk of cognitive impairment, as well as for targeted intervention. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Detection and effects of harmful algal toxins in Scottish harbour seals and potential links to population decline.

PubMed

Jensen, Silje-Kristin; Lacaze, Jean-Pierre; Hermann, Guillaume; Kershaw, Joanna; Brownlow, Andrew; Turner, Andrew; Hall, Ailsa

2015-04-01

Over the past 15 years or so, several Scottish harbour seal (Phoca vitulina) populations have declined in abundance and several factors have been considered as possible causes, including toxins from harmful algae. Here we explore whether a link could be established between two groups of toxins, domoic acid (DA) and saxitoxins (STXs), and the decline in the harbour seal populations in Scotland. We document the first evidence that harbour seals are exposed to both DA and STXs from consuming contaminated fish. Both groups of toxins were found in urine and faeces sampled from live captured (n = 162) and stranded animals (n = 23) and in faecal samples collected from seal haul-out sites (n = 214) between 2008 and 2013. The proportion of positive samples and the toxins levels measured in the excreta were significantly higher in areas where harbour seal abundance is in decline. There is also evidence that DA has immunomodulatory effects in harbour seals, including lymphocytopenia and monocytosis. Scottish harbour seals are exposed to DA and STXs through contaminated prey at potentially lethal levels and with this evidence we suggest that exposure to these toxins are likely to be important factors driving the harbour seal decline in some regions of Scotland. Copyright © 2015 Elsevier Ltd. All rights reserved.

Long-term trajectories of lower extremity function in older adults: estimating gender differences while accounting for potential mortality bias.

PubMed

Botoseneanu, Anda; Allore, Heather G; Gahbauer, Evelyne A; Gill, Thomas M

2013-07-01

Gender-specific trajectories of lower extremity function (LEF) and the potential for bias in LEF estimation due to differences in survival have been understudied. We evaluated longitudinal data from 690 initially nondisabled adults age 70 or older from the Precipitating Events Project. LEF was assessed every 18 months for 12 years using a modified Short Physical Performance Battery (mSPPB). Hierarchical linear models with adjustments for length-of-survival estimated the intraindividual trajectory of LEF and differences in trajectory intercept and slope between men and women. LEF declined following a nonlinear trajectory. In the full sample, and among participants with high (mSPPB 10-12) and intermediate (mSPPB 7-9) baseline LEF, the rate-of-decline in mSPPB was slower in women than in men, with no gender differences in baseline mSPPB scores. Among participants with low baseline LEF (mSPPB ≤6), men had a higher starting mSPPB score, whereas women experienced a deceleration in the rate-of-decline over time. In all groups, participants who survived longer had higher starting mSPPB scores and slower rates-of-decline compared with those who died sooner. Over the course of 12 years, older women preserve LEF better than men. Nonadjustment for differences in survival results in overestimating the level and underestimating the rate-of-decline in LEF over time.

Nonstructural leaf carbohydrate dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism.

PubMed

Adams, Henry D; Germino, Matthew J; Breshears, David D; Barron-Gafford, Greg A; Guardiola-Claramonte, Maite; Zou, Chris B; Huxman, Travis E

2013-03-01

Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function. We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

An evaluation of bur oak (Quercus macrocarpa) decline in the urban forest of Winnipeg, Manitoba, Canada

USGS Publications Warehouse

Catton, H.A.; St., George; Remphrey, W.R.

2007-01-01

Winnipeg, Manitoba, Canada, has a large, indigenous population of bur oak (Quercus macrocarpa Michx.). In the 1980s, many of these trees were showing signs of decline, a disease caused by a complex of abiotic and secondary biotic stressing agents. Potential causal factors were investigated by comparing various aspects of 120 bur oaks visually rated as healthy or declined based on crown dieback levels. The results indicated that many selected bur oak trees predated surrounding urban development and that declined trees were significantly older with more severe stem wounds and competition from surrounding trees than healthy specimens. Average annual growth ring widths of healthy and declined trees were similar in the early part of the 20th century. However, decline actually began decades before symptoms were noticed, coinciding with a period of in tense city-wide urban development, as growth of declined trees was slower than that of healthy trees beginning sporadically in the 1940s and consistently from 1974 to 2001. During the early years of decline, the year-by-year separation in ring width between the two categories was significantly positively related to precipitation levels. This suggested that in wet years, declined trees may have been surrounded by unfavorable water-logged soils, possibly as a result of natural drainage patterns being impeded by urban development. ?? 2007 International Society of Arboriculture.

What can we learn from trial decliners about improving recruitment? Qualitative study.

PubMed

Hughes-Morley, Adwoa; Young, Bridget; Hempel, Roelie J; Russell, Ian T; Waheed, Waquas; Bower, Peter

2016-10-12

Trials increasingly experience problems in recruiting participants. Understanding the causes of poor recruitment is critical to developing solutions. We interviewed people who had declined a trial of an innovative psychological therapy for depression (REFRAMED) about their response to the trial invitation, in order to understand their decision and identify ways to improve recruitment. Of 214 people who declined the trial, 35 (16 %) gave permission to be contacted about a qualitative study to explore their decision. Analysis of transcripts of semi-structured interviews was informed by grounded theory. We interviewed 20 informants: 14 women and six men, aged 18 to 77 years. Many interviewees had prior experience of research participation and positive views of the trial. Interviewees' decision making resembled a four-stage sequential process; in each stage they either decided not to participate in the trial or progressed to the next stage. In stage 1, interviewees assessed the invitation in the context of their experiences and attitudes; we term those who opted out at this stage 'prior decliners' as they had an established position of declining trials. In stage 2, interviewees assessed their own eligibility; those who judged themselves ineligible and opted out at this stage are termed 'self-excluders'. In stage 3, interviewees assessed their need for the trial therapy and potential to benefit; we term those who decided they did not need the trial therapy and opted out at this stage 'treatment decliners'. In stage 4, interviewees deliberated the benefits and costs of trial participation; those who opted out after judging that disadvantages outweighed advantages are termed 'trial decliners'. Across all stages, most individuals declined because they judged themselves ineligible or not in need of the trial therapy. While 'prior decliners' are unlikely to respond to any trial recruitment initiative, the factors leading others to decline are amenable to amelioration as they do not arise from a rejection of trials or a personal stance. To improve recruitment in similar trials, the most successful interventions are likely to address patients' assessments of their eligibility and their potential to benefit from the trial treatment, rather than reducing trial burden. International Standard Randomised Controlled Trial Number: ISRCTN85784627 . Registration date 10 August 2011.

Anomalous rise in algal production linked to lakewater calcium decline through food web interactions

PubMed Central

Korosi, Jennifer B.; Burke, Samantha M.; Thienpont, Joshua R.; Smol, John P.

2012-01-01

Increased algal blooms are a threat to aquatic ecosystems worldwide, although the combined effects of multiple stressors make it difficult to determine the underlying causes. We explore whether changes in trophic interactions in response to declining calcium (Ca) concentrations, a water quality issue only recently recognized in Europe and North America, can be linked with unexplained bloom production. Using a palaeolimnological approach analysing the remains of Cladocera (herbivorous grazers) and visual reflectance spectroscopically inferred chlorophyll a from the sediments of a Nova Scotia (Canada) lake, we show that a keystone grazer, Daphnia, declined in the early 1990s and was replaced by a less effective grazer, Bosmina, while inferred chlorophyll a levels tripled at constant total phosphorus (TP) concentrations. The decline in Daphnia cannot be attributed to changes in pH, thermal stratification or predation, but instead is linked to declining lakewater [Ca]. The consistency in the timing of changes in Daphnia and inferred chlorophyll a suggests top-down control on algal production, providing, to our knowledge, the first evidence of a link between lakewater [Ca] decline and elevated algal production mediated through the effects of [Ca] decline on Daphnia. [Ca] decline has severe implications for whole-lake food webs, and presents yet another mechanism for potential increases in algal blooms. PMID:21957138

With Declining Number of High School Graduates, Where Do We Find Enough Students for Our Colleges in the 1980's?

ERIC Educational Resources Information Center

Otto, George

Community colleges, facing a decline in the 18 to 24 year old college age population, should adopt the marketing philosophy of private enterprise to discover and meet the unsatisfied educational needs of non-traditional, though potential, clients. The adoption of this philosophy, while necessitating that colleges provide education on terms…

Soluble sugar composition of pond-cypress: a potential hydroecological indicator of ground water perturbations

Treesearch

Sydney T. Bacchus; Toshihide Hamazaki; Bruce L. Haines

2000-01-01

Pond-cypress, a deciduous conifer , is a dominant canopy species in depressional wetlands of the southeastern Coastal Plain (SCP). Extensive premature decline and death of pond-cypress trees in central Florida have been attributed to hydroperiod alterations due to excessive withdrawals of ground water from the Floridan aquifer. One factor identified in the decline...

The role of windstorm exposure and yellow cedar decline on landslide susceptibility in southeast Alaskan temperate rainforests

Treesearch

Brian Buma; Adelaide C. Johnson

2015-01-01

Interactions between ecological disturbances have the potential to alter other disturbances and their associated regimes, such as the likelihood, severity, and extent of events. The influence of exposure to wind and yellow cedar decline on the landslide regime of Alaskan temperate rainforests was explored using presence-only modeling techniques. The wind regime was...

Motor Skills Enhance Procedural Memory Formation and Protect against Age-Related Decline

PubMed Central

Müller, Nils C. J.; Genzel, Lisa; Konrad, Boris N.; Pawlowski, Marcel; Neville, David; Fernández, Guillén; Steiger, Axel

2016-01-01

The ability to consolidate procedural memories declines with increasing age. Prior knowledge enhances learning and memory consolidation of novel but related information in various domains. Here, we present evidence that prior motor experience–in our case piano skills–increases procedural learning and has a protective effect against age-related decline for the consolidation of novel but related manual movements. In our main experiment, we tested 128 participants with a sequential finger-tapping motor task during two sessions 24 hours apart. We observed enhanced online learning speed and offline memory consolidation for piano players. Enhanced memory consolidation was driven by a strong effect in older participants, whereas younger participants did not benefit significantly from prior piano experience. In a follow up independent control experiment, this compensatory effect of piano experience was not visible after a brief offline period of 30 minutes, hence requiring an extended consolidation window potentially involving sleep. Through a further control experiment, we rejected the possibility that the decreased effect in younger participants was caused by training saturation. We discuss our results in the context of the neurobiological schema approach and suggest that prior experience has the potential to rescue memory consolidation from age-related cognitive decline. PMID:27333186

Disparities in Temporal and Geographic Patterns of Declining Heart Disease Mortality by Race and Sex in the United States, 1973-2010.

PubMed

Vaughan, Adam S; Quick, Harrison; Pathak, Elizabeth B; Kramer, Michael R; Casper, Michele

2015-12-15

Examining small-area differences in the strength of declining heart disease mortality by race and sex provides important context for current racial and geographic disparities and identifies localities that could benefit from targeted interventions. We identified and described temporal trends in declining county-level heart disease mortality by race, sex, and geography between 1973 and 2010. Using a Bayesian hierarchical model, we estimated age-adjusted mortality with diseases of the heart listed as the underlying cause for 3099 counties. County-level percentage declines were calculated by race and sex for 3 time periods (1973-1985, 1986-1997, 1998-2010). Strong declines were statistically faster or no different than the total national decline in that time period. We observed county-level race-sex disparities in heart disease mortality trends. Continual (from 1973 to 2010) strong declines occurred in 73.2%, 44.6%, 15.5%, and 17.3% of counties for white men, white women, black men, and black women, respectively. Delayed (1998-2010) strong declines occurred in 15.4%, 42.0%, 75.5%, and 76.6% of counties for white men, white women, black men, and black women, respectively. Counties with the weakest patterns of decline were concentrated in the South. Since 1973, heart disease mortality has declined substantially for these race-sex groups. Patterns of decline differed by race and geography, reflecting potential disparities in national and local drivers of these declines. Better understanding of racial and geographic disparities in the diffusion of heart disease prevention and treatment may allow us to find clues to progress toward racial and geographic equity in heart disease mortality. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Height, weight and body mass index values of mid-19th century New York legislative officers.

PubMed

Bodenhorn, Howard

2010-07-01

Previous studies of mid-19th century American heights and body mass index values have used potentially unrepresentative groups-students in military academies, prisoners, and African Americans. This paper uses an alternative source with heights and weights of ordinary people employed in a wide variety of occupations. The results reveal the operation of the antebellum paradox in that average heights declined between men born circa 1820 and those born circa 1840. Average weights also declined for adult males, suggesting a decline in mid-19th century nutritional status. 2010 Elsevier B.V. All rights reserved.

Carbon dioxide (CO2) levels this century will alter the protein, micronutrients, and vitamin content of rice grains with potential health consequences for the poorest rice-dependent countries

PubMed Central

Zhu, Jianguo; Jiang, Qian; Xu, Xi; Liu, Gang; Ebi, Kristie L.; Drewnowski, Adam

2018-01-01

Declines of protein and minerals essential for humans, including iron and zinc, have been reported for crops in response to rising atmospheric carbon dioxide concentration, [CO2]. For the current century, estimates of the potential human health impact of these declines range from 138 million to 1.4 billion, depending on the nutrient. However, changes in plant-based vitamin content in response to [CO2] have not been elucidated. Inclusion of vitamin information would substantially improve estimates of health risks. Among crop species, rice is the primary food source for more than 2 billion people. We used multiyear, multilocation in situ FACE (free-air CO2 enrichment) experiments for 18 genetically diverse rice lines, including Japonica, Indica, and hybrids currently grown throughout Asia. We report for the first time the integrated nutritional impact of those changes (protein, micronutrients, and vitamins) for the 10 countries that consume the most rice as part of their daily caloric supply. Whereas our results confirm the declines in protein, iron, and zinc, we also find consistent declines in vitamins B1, B2, B5, and B9 and, conversely, an increase in vitamin E. A strong correlation between the impacts of elevated [CO2] on vitamin content based on the molecular fraction of nitrogen within the vitamin was observed. Finally, potential health risks associated with anticipated CO2-induced deficits of protein, minerals, and vitamins in rice were correlated to the lowest overall gross domestic product per capita for the highest rice-consuming countries, suggesting potential consequences for a global population of approximately 600 million. PMID:29806023

Carbon dioxide (CO2) levels this century will alter the protein, micronutrients, and vitamin content of rice grains with potential health consequences for the poorest rice-dependent countries.

PubMed

Zhu, Chunwu; Kobayashi, Kazuhiko; Loladze, Irakli; Zhu, Jianguo; Jiang, Qian; Xu, Xi; Liu, Gang; Seneweera, Saman; Ebi, Kristie L; Drewnowski, Adam; Fukagawa, Naomi K; Ziska, Lewis H

2018-05-01

Declines of protein and minerals essential for humans, including iron and zinc, have been reported for crops in response to rising atmospheric carbon dioxide concentration, [CO 2 ]. For the current century, estimates of the potential human health impact of these declines range from 138 million to 1.4 billion, depending on the nutrient. However, changes in plant-based vitamin content in response to [CO 2 ] have not been elucidated. Inclusion of vitamin information would substantially improve estimates of health risks. Among crop species, rice is the primary food source for more than 2 billion people. We used multiyear, multilocation in situ FACE (free-air CO 2 enrichment) experiments for 18 genetically diverse rice lines, including Japonica, Indica, and hybrids currently grown throughout Asia. We report for the first time the integrated nutritional impact of those changes (protein, micronutrients, and vitamins) for the 10 countries that consume the most rice as part of their daily caloric supply. Whereas our results confirm the declines in protein, iron, and zinc, we also find consistent declines in vitamins B1, B2, B5, and B9 and, conversely, an increase in vitamin E. A strong correlation between the impacts of elevated [CO 2 ] on vitamin content based on the molecular fraction of nitrogen within the vitamin was observed. Finally, potential health risks associated with anticipated CO 2 -induced deficits of protein, minerals, and vitamins in rice were correlated to the lowest overall gross domestic product per capita for the highest rice-consuming countries, suggesting potential consequences for a global population of approximately 600 million.

Perceived Personal Control Buffers Terminal Decline in Well-Being

PubMed Central

Gerstorf, Denis; Heckhausen, Jutta; Ram, Nilam; Infurna, Frank J.; Schupp, Juergen; Wagner, Gert G.

2015-01-01

Recent research has repeatedly demonstrated that well-being typically evinces precipitous deterioration close to the end of life. However, the determinants of individual differences in these terminal declines are note well understood. In this study, we examine the role of perceived personal control as a potential buffer against steep terminal declines in well-being. We applied single- and multi-phase growth models to up to 25-year longitudinal data from 1,641 now deceased participants of the national German Socio-Economic Panel Study (SOEP; age at death: M = 74 years; SD = 14; 49% women). Results revealed that perceiving more personal control over one’s life was related to subsequently higher late-life well-being, less severe rates of late-life declines, and a later onset of terminal decline. Associations were independent of key predictors of mortality, including age, gender, SES, and disability. These findings suggest that feeling in control may ameliorate steep end-of-life decline in well-being. We also discuss scenarios for when and how processes of goal disengagement and giving up control may become beneficial. PMID:25244480

Dealing with China's future population decline: a proposal for replacing low birth rates with sustainable rates.

PubMed

Cao, Shixiong; Wang, Xiuqing

2009-09-01

Decreasing population levels due to declining birth rates are becoming a potentially serious social problem in developed and rapidly developing countries. China urgently needed to reduce birth rates so that its population would decline to a sustainable level, and the family planning policy designed to achieve this goal has largely succeeded. However, continuing to pursue this policy is leading to serious, unanticipated problems such as a shift in the country's population distribution towards the elderly and increasing difficulty supporting that elderly population. Social and political changes that promoted low birth rates and the lack of effective policies to encourage higher birth rates suggest that mitigating the consequences of the predicted population decline will depend on a revised approach based on achieving sustainable birth rates.

Childhood Cognitive Ability and Age-Related Changes in Physical Capability From Midlife: Findings From a British Birth Cohort Study.

PubMed

Cooper, Rachel; Richards, Marcus; Kuh, Diana

2017-09-01

The aim of the study was to test the hypothesis that higher childhood cognitive ability is associated with reduced risk of decline in physical capability in late midlife. Participants were 1954 men and women from the Medical Research Council National Survey of Health and Development with complete data on cognitive ability at age of 15 years and measures of grip strength and chair rise speed at ages of 53 and 60 to 64 years. Using multinomial logistic regression, associations of childhood cognitive ability with categories of change in grip strength and chair rise speed (i.e., decline, stable high, stable low, reference) were investigated. Adjustments were made for potential confounders from early life and adult mediators including health behaviors, educational level, and cognitive ability at age of 53 years. Higher childhood cognitive scores were associated with reduced risks of decline in grip strength and chair rise speed, for example, the sex-adjusted relative-risk ratio of decline (versus reference) in grip strength per 1SD increase in childhood cognitive score was 0.82 (95% confidence interval = 0.73-0.92). Higher childhood cognitive scores were also associated with reduced risk of stable low and increased likelihood of stable high chair rise speed. These findings suggest that childhood cognitive ability may be related to decline in physical capability in late midlife. A number of life course pathways are implicated, including those linking childhood and adult cognitive ability. Future research aiming to identify new opportunities to prevent or minimize age-related declines in physical capability may benefit from considering the potential role of neurodevelopmental as well as neurodegenerative pathways.

On the Process and Consequences of Job Rationing in Oregon's Declining Wood Products Industry. WRDC Discussion Paper No. 4.

ERIC Educational Resources Information Center

Stevens, Joe B.; And Others

The study of the mobility of the wood products labor force was made in response to a predicted decline in manpower needs for the wood products industry in western Oregon and western Washington. Variables affecting workers' employability and mobility were analyzed to determine the potential in Oregon for mobility within and out of the industry, the…

Influence of age of males and nutritional condition on short- and long-term reproductive success of elk.

Treesearch

James H. Noyes; Bruce K. Johnson; Brian L. Dick; John G. Kie

2004-01-01

Rocky Mountain elk (Cervus elaphus) populations in some areas of northeastern Oregon have experienced declines in spring calf to cow ratios of nearly 80 percent over the last 40 years. Among the potential causes of these declines, the effects of age of male sires and the nutritional condition of females on conception dates and pregnancy rates have...

[Predictors of verbal memory decline following temporal lobe surgery].

PubMed

de Vanssay-Maigne, A; Boutin, M; Baudoin-Chial, S

2008-05-01

Verbal memory decline can occur after temporal lobe surgery, especially when the left dominant hemisphere is involved. This potential functional risk must be evaluated before surgery. Among all factors that have been identified by several studies, the side of surgery (left dominant) and high baseline memory performance have been found to be predictive of verbal memory decline. Other factors such as etiology, sex, age at surgery, age at seizure onset, and duration may influence memory decline, but the results are not clear. Our purpose was to identify, in our population of patients and among all risk factors, those that may be predictive of verbal memory decline. Logistic regression was used to examine the effect of each factor on the postoperative verbal memory index (WMS-R) in 101 patients who underwent a right (n=49) or left (n=52) anterior temporal lobe resection. In the group as a whole, 22 % of the patients demonstrated verbal memory decline of more than one standard deviation. The verbal memory decline was significantly related to surgery on the left side and a high level of verbal memory performance. These factors were significant predictors of decline. The other factors (etiology, sex, age at surgery, age at seizure onset, and duration) were not found to be predictive of this decline. Our analysis demonstrates that the patients who are most at risk of undergoing verbal memory deterioration are those who undergo left-sided temporal resection and have good memory scores preoperatively. The contradictions found in the literature about the other factors could be explained by the diversity of the tests and criteria used to assess memory decline.

12 CFR 324.153 - Internal models approach (IMA).

Code of Federal Regulations, 2014 CFR

2014-01-01

... potential decline in value of its modeled equity exposures; (ii) Are commensurate with the size, complexity... produce an estimate of potential losses for its modeled equity exposures that is no less than the estimate of potential losses produced by a VaR methodology employing a 99th percentile one-tailed confidence...

12 CFR 3.153 - Internal models approach (IMA).

Code of Federal Regulations, 2014 CFR

2014-01-01

... models that: (i) Assess the potential decline in value of its modeled equity exposures; (ii) Are...) The national bank's or Federal savings association's model must produce an estimate of potential losses for its modeled equity exposures that is no less than the estimate of potential losses produced by...

Citation rate and perceived subject bias in the amphibian-decline literature.

PubMed

Ohmer, Michel E; Bishop, Phillip J

2011-02-01

As a result of global declines in amphibian populations, interest in the conservation of amphibians has grown. This growth has been fueled partially by the recent discovery of other potential causes of declines, including chytridiomycosis (the amphibian chytrid, an infectious disease) and climate change. It has been proposed that researchers have shifted their focus to these novel stressors and that other threats to amphibians, such as habitat loss, are not being studied in proportion to their potential effects. We tested the validity of this proposal by reviewing the literature on amphibian declines, categorizing the primary topic of articles within this literature (e.g., habitat loss or UV-B radiation) and comparing citation rates among articles on these topics and impact factors of journals in which the articles were published. From 1990 to 2009, the proportion of papers on habitat loss remained fairly constant, and although the number of papers on chytridiomycosis increased after the disease was described in 1998, the number of published papers on amphibian declines also increased. Nevertheless, papers on chytridiomycosis were more highly cited than papers not on chytridiomycosis and were published in journals with higher impact factors on average, which may indicate this research topic is more popular in the literature. Our results were not consistent with a shift in the research agenda on amphibians. We believe the perception of such a shift has been supported by the higher citation rates of papers on chytridiomycosis. ©2010 Society for Conservation Biology.

Is air pollution associated with increased risk of cognitive decline? A systematic review.

PubMed

Peters, Ruth; Peters, Jean; Booth, Andrew; Mudway, Ian

2015-09-01

exposure to air pollution has been shown to increase risk of inflammatory processes and risk of cardiovascular mortality. Such exposure may therefore also be a risk factor for cognitive impairment/dementia. a systematic review of the literature was conducted with databases searched using keywords for air pollution, cognitive decline and dementia. All identified abstracts and potentially relevant articles were double read. For those papers meeting the inclusion criteria, summary tables were prepared and papers quality assessed. from 1,551 abstracts identified, 10 articles were retrieved of which two were rejected. Of the eight remaining six reported prevalent cognitive assessment with historical pollution exposure and two incident cognitive decline, also with historical pollution exposure. In general, an association was reported between exposure and poorer prevalent measures of cognitive function. Data were mixed for incident cognitive decline with one study finding an association and the other not. Reports were limited by a lack of detailed reporting, use of proxy measures of pollution exposure and a lack of clarity regarding cognitive testing methodology and analysis. this systematic review highlights that there is some evidence of a potential association between air pollution and subsequent cognitive decline. Further work is clearly required and longitudinal analysis of ongoing cohort studies or new research would add much needed clarity to this area. © The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Contrasting Olfaction, Vision, and Audition as Predictors of Cognitive Change and Impairment in Non-Demented Older Adults

PubMed Central

MacDonald, Stuart W.S.; Keller, Connor J.C.; Brewster, Paul W.H.; Dixon, Roger A.

2017-01-01

Objective This study examines the relative utility of a particular class of non-invasive functional biomarkers -- sensory functions -- for detecting those at risk of cognitive decline and impairment. Three central research objectives were examined including whether: (1) olfactory function, vision, and audition exhibited significant longitudinal declines in non-demented older adults, (2) multi-wave change for these sensory function indicators predicted risk of mild cognitive impairment, and (3) change within persons for each sensory measure shared dynamic time-varying associations with within-person change in cognitive functioning. Method A longitudinal sample (n=408) from the Victoria Longitudinal Study was assembled. Three cognitive status subgroups were identified: not impaired cognitively (NIC), single assessment mild cognitive impairment (SA-MCI), and multiple assessment mild cognitive impairment (MA-MCI). Results We tested independent predictive associations, contrasting change in sensory function as predictors of cognitive decline and impairment, utilizing both linear mixed models and logistic regression analysis. Olfaction and, to a lesser extent, vision were identified as the most robust predictors of cognitive status and decline; audition showed little predictive influence. Conclusions These findings underscore the potential utility of deficits in olfactory function, in particular, as an early marker of age- and pathology-related cognitive decline. Functional biomarkers may represent potential candidates for use in the early stages of a multi-step screening approach for detecting those at risk of cognitive impairment, as well as for targeted intervention. PMID:29809033

Expression of alpha and beta subunit isoforms of Na,K-ATPase in the mouse inner ear and changes with mutations at the Wv or Sld loci.

PubMed

Schulte, B A; Steel, K P

1994-07-01

Mice homozygous for mutations at the viable dominant spotting (Wv) and Steel-dickie (Sld) loci exhibit a similar phenotype which includes deafness. The auditory dysfunction derives from failure of the stria vascularis to develop normally and to generate a high positive endocochlear potential (EP). Because strial function is driven by Na,K-ATPase its expression was investigated in inner ears of Wv/Wv and Sld/Sld mice and their wild-type littermates by immunostaining with antisera against four of the enzyme's subunit isoforms. Wild-type mice from two different genetic backgrounds showed an identical distribution of subunit isoforms among inner ear transport cells. Several epithelial cell types coexpressed the alpha 1 and beta 1 subunits. Vestibular dark cells showed no reactivity for beta 1 but expressed abundant beta 2, whereas, strial marginal cells stained strongly for both beta isoforms. The only qualitative difference between mutant and wild-type mice was the absence of beta 1 subunit in marginal cells of the mutant's stria. However, it is unlikely that this difference accounts for failure of mutants to generate a high EP because the beta 1 subunit is not present in the stria vascularis of either rats or gerbils with normal EP values. Strong immunostaining for Na,K-ATPase in lateral wall fibrocytes of normal mice along with diminished immunoreactivity in the mutants supports the concept that these strategically located transport fibrocytes actively resorb K+ leaked across Reissner's membrane into scala vestibuli or effluxed from hair cells and nerves into scala tympani. It is further speculated that the resorbed K+ normally is siphoned down its concentration gradient into the intrastrial space through gap junctions between fibrocytes and strial basal and intermediate cells where it is recycled back to endolymph via marginal cells. Thus, failure of mutants to generate a positive EP could be explained by the absence of intermediate cells which may form the final link in the conduit for moving K+ from perilymph to the intrastrial compartment.

Insulin-like Growth Factor 1 (IGF-1) as a marker of cognitive decline in normal ageing: A review.

PubMed

Frater, Julanne; Lie, David; Bartlett, Perry; McGrath, John J

2018-03-01

Insulin-like Growth Factor 1 (IGF-1) and its signaling pathway play a primary role in normal growth and ageing, however serum IGF-1 is known to reduce with advancing age. Recent findings suggest IGF-1 is essential for neurogenesis in the adult brain, and this reduction of IGF-1 with ageing may contribute to age-related cognitive decline. Experimental studies have shown manipulation of the GH/GF-1 axis can slow rates of cognitive decline in animals, making IGF-1 a potential biomarker of cognition, and/or its signaling pathway a possible therapeutic target to prevent or slow age-related cognitive decline. A systematic literature review and qualitative narrative summary of current evidence for IGF-1 as a biomarker of cognitive decline in the ageing brain was undertaken. Results indicate IGF-1 concentrations do not confer additional diagnostic information for those with cognitive decline, and routine clinical measurement of IGF-1 is not currently justified. In cases of established cognitive impairment, it remains unclear whether increasing circulating or brain IGF-1 may reverse or slow down the rate of further decline. Advances in neuroimaging, genetics, neuroscience and the availability of large well characterized biobanks will facilitate research exploring the role of IGF-1 in both normal ageing and age-related cognitive decline. Copyright © 2017 Elsevier B.V. All rights reserved.

Healthy eating and reduced risk of cognitive decline

PubMed Central

Dehghan, Mahshid; O'Donnell, Martin; Anderson, Craig; Teo, Koon; Gao, Peggy; Sleight, Peter; Dagenais, Gilles; Probstfield, Jeffrey L.; Mente, Andrew; Yusuf, Salim

2015-01-01

Objective: We sought to determine the association of dietary factors and risk of cognitive decline in a population at high risk of cardiovascular disease. Methods: Baseline dietary intake and measures of the Mini-Mental State Examination were recorded in 27,860 men and women who were enrolled in 2 international parallel trials of the ONTARGET (Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial) and TRANSCEND (Telmisartan Randomised Assessment Study in ACE Intolerant Subjects with Cardiovascular Disease) studies. We measured diet quality using the modified Alternative Healthy Eating Index. Cox proportional hazards regression was used to determine the association between diet quality and risk of ≥3-point decline in Mini-Mental State Examination score, and reported as hazard ratio with 95% confidence intervals with adjustment for covariates. Results: During 56 months of follow-up, 4,699 cases of cognitive decline occurred. We observed lower risk of cognitive decline among those in the healthiest dietary quintile of modified Alternative Healthy Eating Index compared with lowest quintile (hazard ratio 0.76, 95% confidence interval 0.66–0.86, Q5 vs Q1). Lower risk of cognitive decline was consistent regardless of baseline cognitive level. Conclusion: We found that higher diet quality was associated with a reduced risk of cognitive decline. Improved diet quality represents an important potential target for reducing the global burden of cognitive decline. PMID:25948720

A call for comparative effectiveness research to learn whether routine clinical care decisions can protect from dementia and cognitive decline.

PubMed

Dacks, Penny A; Armstrong, Joshua J; Brannan, Stephen K; Carman, Aaron J; Green, Allan M; Kirkman, M Sue; Krakoff, Lawrence R; Kuller, Lewis H; Launer, Lenore J; Lovestone, Simon; Merikle, Elizabeth; Neumann, Peter J; Rockwood, Kenneth; Shineman, Diana W; Stefanacci, Richard G; Velentgas, Priscilla; Viswanathan, Anand; Whitmer, Rachel A; Williamson, Jeff D; Fillit, Howard M

2016-08-20

Common diseases like diabetes, hypertension, and atrial fibrillation are probable risk factors for dementia, suggesting that their treatments may influence the risk and rate of cognitive and functional decline. Moreover, specific therapies and medications may affect long-term brain health through mechanisms that are independent of their primary indication. While surgery, benzodiazepines, and anti-cholinergic drugs may accelerate decline or even raise the risk of dementia, other medications act directly on the brain to potentially slow the pathology that underlies Alzheimer's and other dementia. In other words, the functional and cognitive decline in vulnerable patients may be influenced by the choice of treatments for other medical conditions. Despite the importance of these questions, very little research is available. The Alzheimer's Drug Discovery Foundation convened an advisory panel to discuss the existing evidence and to recommend strategies to accelerate the development of comparative effectiveness research on how choices in the clinical care of common chronic diseases may protect from cognitive decline and dementia.

Analysis of Tyrosine Kinase Inhibitor-Mediated Decline in Contractile Force in Rat Engineered Heart Tissue.

PubMed

Jacob, Fabian; Yonis, Amina Y; Cuello, Friederike; Luther, Pradeep; Schulze, Thomas; Eder, Alexandra; Streichert, Thomas; Mannhardt, Ingra; Hirt, Marc N; Schaaf, Sebastian; Stenzig, Justus; Force, Thomas; Eschenhagen, Thomas; Hansen, Arne

2016-01-01

Left ventricular dysfunction is a frequent and potentially severe side effect of many tyrosine kinase inhibitors (TKI). The mode of toxicity is not identified, but may include impairment of mitochondrial or sarcomeric function, autophagy or angiogenesis, either as an on-target or off-target mechanism. We studied concentration-response curves and time courses for nine TKIs in three-dimensional, force generating engineered heart tissue (EHT) from neonatal rat heart cells. We detected a concentration- and time-dependent decline in contractile force for gefitinib, lapatinib, sunitinib, imatinib, sorafenib, vandetanib and lestaurtinib and no decline in contractile force for erlotinib and dasatinib after 96 hours of incubation. The decline in contractile force was associated with an impairment of autophagy (LC3 Western blot) and appearance of autophagolysosomes (transmission electron microscopy). This study demonstrates the feasibility to study TKI-mediated force effects in EHTs and identifies an association between a decline in contractility and inhibition of autophagic flux.

Analysis of Tyrosine Kinase Inhibitor-Mediated Decline in Contractile Force in Rat Engineered Heart Tissue

PubMed Central

Cuello, Friederike; Luther, Pradeep; Schulze, Thomas; Eder, Alexandra; Streichert, Thomas; Mannhardt, Ingra; Hirt, Marc N.; Schaaf, Sebastian; Stenzig, Justus; Force, Thomas

2016-01-01

Introduction Left ventricular dysfunction is a frequent and potentially severe side effect of many tyrosine kinase inhibitors (TKI). The mode of toxicity is not identified, but may include impairment of mitochondrial or sarcomeric function, autophagy or angiogenesis, either as an on-target or off-target mechanism. Methods and Results We studied concentration-response curves and time courses for nine TKIs in three-dimensional, force generating engineered heart tissue (EHT) from neonatal rat heart cells. We detected a concentration- and time-dependent decline in contractile force for gefitinib, lapatinib, sunitinib, imatinib, sorafenib, vandetanib and lestaurtinib and no decline in contractile force for erlotinib and dasatinib after 96 hours of incubation. The decline in contractile force was associated with an impairment of autophagy (LC3 Western blot) and appearance of autophagolysosomes (transmission electron microscopy). Conclusion This study demonstrates the feasibility to study TKI-mediated force effects in EHTs and identifies an association between a decline in contractility and inhibition of autophagic flux. PMID:26840448

Declining oral intake towards the end of life: how to talk about it? A qualitative study.

PubMed

Clark, Jean; Raijmakers, Natasja J H; Allan, Simon; Zuylen, Lia van; Heide, Agnes van der

2017-02-02

Decreasing oral intake is common towards the end of life and a potential source of distress and concern for patients, relatives, whānau and clinicians. This paper provides insight to inform practice regarding clinicians' perceptions, practices, responses and communication with patients and their companions regarding declining oral intake towards the end of life. In this qualitative study ten specialist palliative care staff participated in semi-structured interviews. Qualitative thematic analysis was used to analyse the data. Three themes were identified: declining oral intake was a natural part of the dying process; responding empathetically; and clinicians described specific aims and ways regarding communication. Insight into clinicians' endeavours to manage declining oral intake and support the wellbeing of patients, families, and whānau can inform practice. However the perspectives of family, whānau and health professionals continue to show significant variation regarding the communication given and received around declining oral intake towards the end of life.

Biodiversity losses: The downward spiral

USGS Publications Warehouse

Tomback, Diana F.; Kendall, Katherine C.; Tomback, Diana F.; Arno, Stephen F.; Keane, Robert E.

2001-01-01

The dramatic decline of whitebark pine (Pinus albicaulis) populations in the northwestern United States and southwestern Canada from the combined effects of fire exclusion, mountain pine beetles (Dendroctonus ponderosae), and white pine blister rust (Cronartium ribicola), and the projected decline of whitebark pine populations rangewide (Chapters 10 and 11) do not simply add up to local extirpations of a single tree species. Instead, the loss of whitebark pine has broad ecosystem-level consequences, eroding local plant and animal biodiversity, changing the time frame of succession, and altering the distribution of subalpine vegetation (Chapter 1). One potential casualty of this decline may be the midcontinental populations of the grizzly bear (Ursus arctos horribilis), which use whitebark pine seeds as a major food source (Chapter 7). Furthermore, whitebark pine is linked to other white pine ecosystems in the West through its seed-disperser, Clark's nutcracker (Nucifraga columbiana) (Chapter 5). Major declines in nutcracker populations ultimately seal the fate of several white pine ecosystems, and raise the question of whether restoration is possible once a certain threshold of decline is reached.

[The demographic potential of Russia].

PubMed

Vishnevskii, A

1998-05-01

This is a general review of current demographic trends in Russia. The author analyzes the decline in population size that is taking place at the end of the twentieth century, and traces its origins as far back as the disturbances associated with World War I, the Communist revolution, and the civil war that followed it. Political repression during the Stalinist period and the tribulations experienced during World War II also contributed to the current demographic crisis. The author discusses the changes in migration patterns and the declining fertility and increasing mortality rates. The decline in life expectancy is also addressed. Some comparisons are made with the demographic situation in other European countries.

Contributions of insects and droughts to growth decline of trembling aspen mixed boreal forest of western Canada.

PubMed

Chen, Lei; Huang, Jian-Guo; Dawson, Andria; Zhai, Lihong; Stadt, Kenneth J; Comeau, Philip G; Whitehouse, Caroline

2018-02-01

Insects, diseases, fire and drought and other disturbances associated with global climate change contribute to forest decline and mortality in many parts of the world. Forest decline and mortality related to drought or insect outbreaks have been observed in North American aspen forests. However, little research has been done to partition and estimate their relative contributions to growth declines. In this study, we combined tree-ring width and basal area increment series from 40 trembling aspen (Populus tremuloides Michx.) sites along a latitudinal gradient (from 52° to 58°N) in western Canada and attempted to investigate the effect of drought and insect outbreaks on growth decline, and simultaneously partition and quantify their relative contributions. Results indicated that the influence of drought on forest decline was stronger than insect outbreaks, although both had significant effects. Furthermore, the influence of drought and insect outbreaks showed spatiotemporal variability. In addition, our data suggest that insect outbreaks could be triggered by warmer early spring temperature instead of drought, implicating that potentially increased insect outbreaks are expected with continued warming springs, which may further exacerbate growth decline and death in North America aspen mixed forests. © 2017 John Wiley & Sons Ltd.

Artificial night lighting inhibits feeding in moths

PubMed Central

van Grunsven, Roy H. A.; Veenendaal, Elmar M.

2017-01-01

One major, yet poorly studied, change in the environment is nocturnal light pollution, which strongly alters habitats of nocturnally active species. Artificial night lighting is often considered as driving force behind rapid moth population declines in severely illuminated countries. To understand these declines, the question remains whether artificial light causes only increased mortality or also sublethal effects. We show that moths subjected to artificial night lighting spend less time feeding than moths in darkness, with the shortest time under light conditions rich in short wavelength radiation. These findings provide evidence for sublethal effects contributing to moth population declines. Because effects are strong under various types of light compared with dark conditions, the potential of spectral alterations as a conservation tool may be overestimated. Therefore, restoration and maintenance of darkness in illuminated areas is essential for reversing declines of moth populations. PMID:28250209

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

PubMed Central

Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

2015-01-01

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

Land cover dynamics across the Great Plains and their influence on breeding birds: Potential artefact of data and analysis limitations

Treesearch

C. H. Flather; M. S. Knowles; L. S. Baggett

2017-01-01

The distribution and abundance of obligate grassland breeding birds in the US have declined across the Great Plains as native habitats have been converted to intensive human land use. A major finding of Scholtz et al. (2017: Table 3) was that the group-wise extinction rate among 13 common grassland nesting birds declined with increasing cropland. This conclusion runs...

First report of an Armillaria root disease pathogen, Armillaria gallica, associated with several new hosts in Hawaii

Treesearch

M.-S. Kim; J. W. Hanna; N. B. Klopfenstein

2010-01-01

The loss and decline of native tree species caused by invasive plant pathogens is a major threat to the endangered endemic forests of the Hawaiian Islands (3). Thus, it is critical to characterize existing pathogens to evaluate potential invasiveness. In August 2005, rhizomorphs and mycelial bark fans of genet HI-4 were collected from dead/declining, mature trees of...

Conservation choice on the rare endangered plants Glehnia littoralis.

PubMed

Pan, Yanxia; Chu, Jianmin; Yang, Hongxiao

2018-01-01

The coastal herbs Glehnia littoralis have been domesticated as traditional medicines for many centuries. The domestication may have caused changes or declines of cultivated G. littoralis (CGL) relative to wild G. littoralis (WGL). By comparing fruit properties of CGL and WGL, we tested the hypothesis that domesticated G. littoralis have suffered major declines, and human cultivation cannot be sufficient to conserve this species. We collected fruits of CGL and WGL in the Shandong peninsula, China, and compared their buoyancy in seawater, germination potential after seawater immersion, and thousand-grain weights. Float rates of the WGL and CGL fruits were 95.6 (mean) ± 2.6% (standard deviation) and 30.0 ± 7.1%, respectively. The germination potential of CGL was significantly reduced, although the thousand-grain weights of CGL (21.85 ± 0.17 g) were higher than those of the WGL fruits (14.73 ± 0.21 g). These results suggest that the CGL have experienced significant declines relative to the WGL, presumably due to the loss of seawater inundation, selection and dispersal. These declines disfavour the persistence of CGL, and human domestication and cultivation are believed to be insufficient for conserving G. littoralis . Sand coasts where WGL still persists should be designated timely as nature reserves to conserve this species.

Viewing forests from below: fine root mass declines relative to leaf area in aging lodgepole pine stands.

PubMed

Schoonmaker, A S; Lieffers, V J; Landhäusser, S M

2016-07-01

In the continued quest to explain the decline in productivity and vigor with aging forest stands, the most poorly studied area relates to root system change in time. This paper measures the wood production, root and leaf area (and mass) in a chronosequence of fire-origin lodgepole pine (Pinus contorta Loudon) stands consisting of four age classes (12, 21, 53, and ≥100 years), each replicated ~ five times. Wood productivity was greatest in the 53-year-old stands and then declined in the ≥100-year-old stands. Growth efficiency, the quantity of wood produced per unit leaf mass, steadily declined with age. Leaf mass and fine root mass plateaued between the 53- and ≥100-year-old stands, but leaf area index actually increased in the older stands. An increase in the leaf area index:fine root area ratio supports the idea that older stand are potentially limited by soil resources. Other factors contributing to slower growth in older stands might be lower soil temperatures and increased self-shading due to the clumped nature of crowns. Collectively, the proportionally greater reduction in fine roots in older stands might be the variable that predisposes these forests to be at a potentially greater risk of stress-induced mortality.

Genetics Show Current Decline and Pleistocene Expansion in Northern Spotted Owls

USGS Publications Warehouse

Funk, W. Chris; Forsman, Eric D.; Mullins, Thomas D.; Haig, Susan M.

2008-01-01

The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the U.S. Endangered Species Act. Because of concern for persistence of the subspecies, logging on Federal lands in the U.S. Pacific Northwest was dramatically reduced under the Northwest Forest Plan in 1994. Despite protection of its remaining forest habitat, recent field studies show continued demographic declines of northern spotted owls. One potential threat to northern spotted owls that has not yet been shown is loss of genetic variation from population bottlenecks that can increase inbreeding depression and decrease adaptive potential. Here, we show recent genetic bottlenecks in northern spotted owls using a large genetic dataset (352 individuals from across the subspecies' range and 11 microsatellite loci). The signature of bottlenecks was strongest in Washington State, in agreement with field data. Interestingly, we also found a genetic signature of Pleistocene expansion in the same study areas where recent bottlenecks were shown. Our results provide independent evidence that northern spotted owls have recently declined, and suggest that loss of genetic variation is an emerging threat to the subspecies' persistence. Reduced effective population size (Ne), shown here in addition to field evidence for demographic decline, highlights the increasing vulnerability of this bird to extinction.

Decline of flounder (Platichthys flesus (L.)) at the margin of the species' distribution range

NASA Astrophysics Data System (ADS)

Jokinen, Henri; Wennhage, Håkan; Lappalainen, Antti; Ådjers, Kaj; Rask, Martti; Norkko, Alf

2015-11-01

The Baltic Sea is undergoing large-scale environmental change due to eutrophication, climate change, over-exploitation and habitat destruction, with subsequent degradation of living conditions for many fish species. Signs of this unfavorable development are seen as population declines in species affected. We provide the first synthesis and characterization of the recent population decline in European flounder (Platichthys flesus (L.)) in the northern Baltic Sea, using available fishery-independent data from the Finnish coast, which is at the margin of the distribution range of this species. The objective was to document recent changes in the flounder population, identify the onset and quantify the magnitude of the change. The results showed substantial decreases in flounder numbers and biomass across the whole study area during recent decades. Based on the time series data available, flounder abundances declined by 46-97% from the 1990s to the 2000s, with top values in the mid-1990s and current low levels reached in the early 2000s. Additionally, signs of decreasing flounder size and condition were also observed. We discuss potential reasons for the development in terms of environmental change and fishing, and identify potential bottlenecks for population maintenance and mechanisms behind population change, thereby contributing to our general understanding of marginal flounder populations.

Drought as a driver of declining boreal forest growth: Integrating forest inventory measurements with models to gain insight into underlying mechanisms

NASA Astrophysics Data System (ADS)

Trugman, A. T.; Medvigy, D.; Anderegg, W.; Caspersen, J.; Zeng, H.; Pacala, S. W.

2016-12-01

Boreal forests contain over 30% of Earth's terrestrial carbon and are an important component of the land carbon sink. However, the future ability of the boreal forest to maintain a net carbon sink is uncertain and depends on potentially compensating interactions of CO2 fertilization, warmer temperatures, and hotter drought conditions. Observational studies have attributed drought as a major driver of recent declines in growth and increases in mortality in many parts of the North American boreal forest. Yet, most vegetation models have a simplistic representation of vegetation water stress and fail to capture drought-associated growth and mortality trends, impacting our ability to accurately forecast the effects of climate change on the boreal forest. Here, we show additional evidence for widespread declines in boreal tree growth and increasing insect-related mortality in aspen trees based on a mixed model analysis of the Cooperative Alaska Forest Inventory. Our findings indicate that the growth decline is controlled by high midsummer potential evapotranspiration that overpowers any CO2 fertilization signal. We also observe a possible shift in the distribution of angiosperm and gymnosperm, a biological transition that could impact long-term local carbon dynamics. Using insight gained from our mixed model analysis, we perform a regional-scale model evaluation using the boreal forest version of Ecosystem Demography model 2 that includes a dynamic soil organic layer, 7 boreal-specific plant functional types, and a fully mechanistic plant hydraulic scheme. We then use both the Alaskan and Canadian Forest Inventories to constrain our hypotheses and assess whether drought related growth declines can be better attributed to tree drought response from (1) carbon starvation, (2) permanent damage of hydraulic machinery, or (3) delayed recovery of hydraulic machinery. Under each of these scenarios we forecast how drought potentially impacts decadal-scale boreal carbon dynamics.

Average household exposure to newspaper coverage about the harmful effects of hormone therapy and population-based declines in hormone therapy use.

PubMed

Haas, Jennifer S; Miglioretti, Diana L; Geller, Berta; Buist, Diana S M; Nelson, David E; Kerlikowske, Karla; Carney, Patricia A; Dash, Sarah; Breslau, Erica S; Ballard-Barbash, Rachel

2007-01-01

The news media facilitated the rapid dissemination of the findings from the estrogen plus progestin therapy arm of the Women's Health Initiative (EPT-WHI). To examine the relationship between the potential exposure to newspaper coverage and subsequent hormone therapy (HT) use. DESIGN/POPULATION: Population-based cohort of women receiving mammography at 7 sites (327,144 postmenopausal women). The outcome was the monthly prevalence of self-reported HT use. Circulation data for local, regional, and national newspapers was used to create zip-code level measures of the estimated average household exposure to newspaper coverage that reported the harmful effects of HT in July 2002. Women had an average potential household exposure of 1.4 articles. There was substantial variation in the level of average household exposure to newspaper coverage; women from rural sites received less than women from urban sites. Use of HT declined for all average potential exposure groups after the publication of the EPT-WHI. HT prevalence among women who lived in areas where there was an average household exposure of at least 3 articles declined significantly more (45 to 27%) compared to women who lived in areas with <1 article (43 to 31%) during each of the subsequent 5 months (relative risks 0.86-0.92; p < .006 for all). Greater average household exposure to newspaper coverage about the harms associated with HT was associated with a large population-based decline in HT use. Further studies should examine whether media coverage directly influences the health behavior of individual women.

Ichthyoplankton Time Series: A Potential Ocean Observing Network to Provide Indicators of Climate Impacts on Fish Communities along the West Coast of North America

NASA Astrophysics Data System (ADS)

Koslow, J. A.; Brodeur, R.; Duffy-Anderson, J. T.; Perry, I.; jimenez Rosenberg, S.; Aceves, G.

2016-02-01

Ichthyoplankton time series available from the Bering Sea, Gulf of Alaska and California Current (Oregon to Baja California) provide a potential ocean observing network to assess climate impacts on fish communities along the west coast of North America. Larval fish abundance reflects spawning stock biomass, so these data sets provide indicators of the status of a broad range of exploited and unexploited fish populations. Analyses to date have focused on individual time series, which generally exhibit significant change in relation to climate. Off California, a suite of 24 midwater fish taxa have declined > 60%, correlated with declining midwater oxygen concentrations, and overall larval fish abundance has declined 72% since 1969, a trend based on the decline of predominantly cool-water affinity taxa in response to warming ocean temperatures. Off Oregon, there were dramatic differences in community structure and abundance of larval fishes between warm and cool ocean conditions. Midwater deoxygenation and warming sea surface temperature trends are predicted to continue as a result of global climate change. US, Canadian, and Mexican fishery scientists are now collaborating in a virtual ocean observing network to synthesize available ichthyoplankton time series and compare patterns of change in relation to climate. This will provide regional indicators of populations and groups of taxa sensitive to warming, deoxygenation and potentially other stressors, establish the relevant scales of coherence among sub-regions and across Large Marine Ecosystems, and provide the basis for predicting future climate change impacts on these ecosystems.

Perceptions of oocyte banking from women intending to circumvent age-related fertility decline.

PubMed

de Groot, Marije; Dancet, Eline; Repping, Sjoerd; Goddijn, Mariette; Stoop, Dominic; van der Veen, Fulco; Gerrits, Trudie

2016-12-01

Women can now opt to bank their oocytes with the intention of increasing their chances of achieving a pregnancy after their fertility has declined. This exploratory study aimed to gain insight into how women, considering oocyte banking to circumvent age-related fertility decline, perceive this intervention. We conducted a qualitative study in a Dutch university medical center and held in-depth interviews with women on the waiting list for oocyte banking. We recorded the interviews, transcribed them verbatim and used thematic analysis. All women were financially independent and lived in single-person urban households. They opted for oocyte banking because they wished to share parenthood with a future partner rather than becoming a single parent. This strong desire was key in their interpretation of all aspects of the intervention. Women set aside information about the limited success rates and potential risks, as they were optimistic about their own prognosis, thought that the chances for success were equally likely as the chances it would fail, and because of "anticipatory regret". They perceived oocyte banking as a "helping hand" to achieve shared parenthood. Although women found the costs of the intervention high, they were willing to invest their money to increase their chances for shared parenthood. Oocyte banking allows women to circumvent age-related fertility decline. The prospect of potential shared parenthood overrules the perceived health risks and burden. Health professionals should take this into account when informing potential users of oocyte banking. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Assessing the links among environmental contaminants, endocrinology, and parasites to understand amphibian declines in montane regions of Costa Rica.

PubMed

Leary, Christopher J; Ralicki, Hannah F; Laurencio, David; Crocker-Buta, Sarah; Malone, John H

2018-01-01

Amphibians inhabiting montane riparian zones in the Neotropics are particularly vulnerable to decline, but the reasons are poorly understood. Because environmental contaminants, endocrine disruption, and pathogens often figure prominently in amphibian declines it is imperative that we understand how these factors are potentially interrelated to affect montane populations. One possibility is that increased precipitation associated with global warming promotes the deposition of contaminants in montane regions. Increased exposure to contaminants, in turn, potentially elicits chronic elevations in circulating stress hormones that could contribute to montane population declines by compromising resistance to pathogens and/or production of sex steroids regulating reproduction. Here, we test this hypothesis by examining contaminant levels, stress and sex steroid levels, and nematode abundances in male drab treefrogs, Smilisca sordida, from lowland and montane populations in Costa Rica. We found no evidence that montane populations were more likely to possess contaminants (i.e., organochlorine, organophosphate and carbamate pesticides or benzidine and chlorophenoxy herbicides) than lowland populations. We also found no evidence of elevational differences in circulating levels of the stress hormone corticosterone, estradiol or progesterone. However, montane populations possessed lower androgen levels, hosted more nematode species, and had higher nematode abundances than lowland populations. Although these results suggested that nematodes contributed to lower androgens in montane populations, we were unable to detect a significant inverse relationship between nematode abundance and androgen level. Our results suggest that montane populations of this species are not at greater risk of exposure to contaminants or chronic stress, but implicate nematodes and compromised sex steroid levels as potential threats to montane populations.

12 CFR 217.153 - Internal models approach (IMA).

Code of Federal Regulations, 2014 CFR

2014-01-01

...-regulated institution must have one or more models that: (i) Assess the potential decline in value of its... idiosyncratic risk. (2) The Board-regulated institution's model must produce an estimate of potential losses for its modeled equity exposures that is no less than the estimate of potential losses produced by a VaR...

Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis

PubMed Central

Carvalho, Tamilie; Becker, C. Guilherme

2017-01-01

The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungus Batrachochytrium dendrobatidis (Bd) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of several Bd lineages predating the reported declines raised the hypothesis that a hypervirulent Bd genotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap between Bd and areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence between Bd and declines would support the hypothesis that Brazilian amphibians were not adapted to Bd prior to the reported declines, thus weakening the hypothesis that Brazil was the global origin of Bd emergence. Alternatively, a lack of spatio-temporal association between Bd and frog declines would indicate an evolution of host resistance in Brazilian frogs predating Bd's global emergence, further supporting Brazil as the potential origin of the Bd panzootic. Here, we Bd-screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporal Bd data with areas of historical amphibian declines. We detected an increase in the proportion of Bd-infected tadpoles during the peak of amphibian declines (1979–1987). We also found that clusters of Bd-positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin of Bd globally. PMID:28179514

Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical

PubMed Central

Lawes, Michael J.; Fisher, Diana O.; Johnson, Chris N.; Blomberg, Simon P.; Frank, Anke S. K.; Fritz, Susanne A.; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N.; Legge, Sarah; Letnic, Mike; Thomas, Colette R.; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J.; Kutt, Alex

2015-01-01

Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south. PMID:26111037

Historical amphibian declines and extinctions in Brazil linked to chytridiomycosis.

PubMed

Carvalho, Tamilie; Becker, C Guilherme; Toledo, Luís Felipe

2017-02-08

The recent increase in emerging fungal diseases is causing unprecedented threats to biodiversity. The origin of spread of the frog-killing fungus Batrachochytrium dendrobatidis ( Bd ) is a matter of continued debate. To date, the historical amphibian declines in Brazil could not be attributed to chytridiomycosis; the high diversity of hosts coupled with the presence of several Bd lineages predating the reported declines raised the hypothesis that a hypervirulent Bd genotype spread from Brazil to other continents causing the recent global amphibian crisis. We tested for a spatio-temporal overlap between Bd and areas of historical amphibian population declines and extinctions in Brazil. A spatio-temporal convergence between Bd and declines would support the hypothesis that Brazilian amphibians were not adapted to Bd prior to the reported declines, thus weakening the hypothesis that Brazil was the global origin of Bd emergence. Alternatively, a lack of spatio-temporal association between Bd and frog declines would indicate an evolution of host resistance in Brazilian frogs predating Bd 's global emergence , further supporting Brazil as the potential origin of the Bd panzootic. Here, we Bd -screened over 30 000 museum-preserved tadpoles collected in Brazil between 1930 and 2015 and overlaid spatio-temporal Bd data with areas of historical amphibian declines. We detected an increase in the proportion of Bd -infected tadpoles during the peak of amphibian declines (1979-1987). We also found that clusters of Bd -positive samples spatio-temporally overlapped with most records of amphibian declines in Brazil's Atlantic Forest. Our findings indicate that Brazil is post epizootic for chytridiomycosis and provide another piece to the puzzle to explain the origin of Bd globally. © 2017 The Author(s).

Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical.

PubMed

Lawes, Michael J; Fisher, Diana O; Johnson, Chris N; Blomberg, Simon P; Frank, Anke S K; Fritz, Susanne A; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N; Legge, Sarah; Letnic, Mike; Thomas, Colette R; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J; Kutt, Alex

2015-01-01

Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south.

T-Tau is Associated with Objective Memory Decline Over Two Years in Persons Seeking Help for Subjective Cognitive Decline: A Report from the Gothenburg-Oslo MCI Study.

PubMed

Hessen, Erik; Nordlund, Arto; Stålhammar, Jacob; Eckerström, Marie; Bjerke, Maria; Eckerström, Carl; Göthlin, Mattias; Fladby, Tormod; Reinvang, Ivar; Wallin, Anders

2015-01-01

There is a need to find very early markers for pre-clinical Alzheimer's disease as interventions early in the disease process are thought to be most effective. The present study aimed to address the potential relation between cerebrospinal fluid (CSF) biomarkers and reduced cognitive function in a relatively young cohort of memory clinic patients with subjective cognitive decline. 122 patients (mean age 63 years) with subjective cognitive decline were recruited from two university memory clinics and followed for two years. The main finding was that the subgroup with objective memory decline during the study period had significantly higher T-tau at baseline than the group with improved memory. Baseline CSF variables showed a trend toward more pathological values in the patients with memory decline compared to those who improved or remained stable. The baseline memory score of those who declined was significantly better than the baseline score of those who improved over two years. The general trend for the whole group was improved memory and executive test scores. There were no differences in cognitive scores based on CSF quartiles at baseline, nor were there differences in cognitive outcome for patients with early amnestic mild cognitive impairment versus average cognitive function at baseline. The main finding that T-tau rather than amyloid-β was associated with memory decline do not support the prevailing opinion about the chain of events assumed to take place in Alzheimer's disease. In addition, memory decline was not associated with poor baseline memory score. Thus, a memory cut-off indicating low baseline memory would not would have identified the declining group.

Factors Influencing the Decline in Stroke Mortality

PubMed Central

Lackland, Daniel T.; Roccella, Edward J.; Deutsch, Anne; Fornage, Myriam; George, Mary G.; Howard, George; Kissela, Brett; Kittner, Steven J.; Lichtman, Judith H.; Lisabeth, Lynda; Schwamm, Lee H.; Smith, Eric E.; Towfighi, Amytis

2017-01-01

Background and Purpose Stroke mortality has been declining since the early twentieth century. The reasons for this are not completely understood, although the decline is welcome. As a result of recent striking and more accelerated decreases in stroke mortality, stroke has fallen from the third to the fourth leading cause of death in the United States. This has prompted a detailed assessment of the factors associated with this decline. This review considers the evidence of various contributors to the decline in stroke risk and mortality and can be used in the design of future interventions regarding this major public health burden. Methods Writing group members were nominated by the committee chair and co-chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council’s Scientific Statement Oversight Committee and the AHA’s Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize evidence and indicate gaps in current knowledge. All members of the writing group had the opportunity to comment and approved the final version of this document. The document underwent extensive AHA internal peer review, Stroke Council Leadership review and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee. Results The decline in stroke mortality over the past decades represents a major improvement in population health and is observed for both genders, and all race and age groups. In addition to the overall impact on fewer lives lost to stroke, the major decline in stroke mortality seen among individuals less than 65 years of age represents a reduction on years of potential life lost. The decline in mortality results from reduced stroke incidence and lower case fatality rates. These significant improvements in stroke outcomes are concurrent with cardiovascular risk factor control interventions. While it is difficult to calculate specific attributable risk estimates, the hypertension control efforts initiated in the 1970s appears to have had the most substantial influence on the accelerated stroke mortality decline. Although implemented later in the time period, diabetes and dyslipidemia control and smoking cessation programs, particularly in combination with hypertension treatment, also appear to have contributed to the stroke mortality decline. Telemedicine and stroke systems of care, while showing strong potential effects, have not been in place long enough to show their influence on the decline. Other factors had probable effects, but additional studies are needed to determine their contributions. Conclusion The decline in stroke mortality is real and represents a major public health and clinical medicine success story. The repositioning of stroke from 3rd to 4th leading cause of death is the result of true mortality decline and not an increase of chronic lung disease mortality, which is now the 3rd leading cause of death in the United States. There is strong evidence the decline can be attributed to a combination of interventions and programs based on scientific findings and implemented with the purpose to reduce stroke risks, the most likely being improved hypertension control. Thus, research studies and the application of their findings to develop intervention programs have improved the health of the population. The continued application of aggressive evidence-based public health programs and clinical interventions are expected to result in further declines in stroke mortality. PMID:24309587

Human Population Decline in North America during the Younger Dryas

NASA Astrophysics Data System (ADS)

Anderson, D. G.; Goodyear, A. C.; Stafford, T. W., Jr.; Kennett, J.; West, A.

2009-12-01

There is ongoing debate about a possible human population decline or contraction at the onset of the Younger Dryas (YD) at 12.9 ka. We used two methods to test whether the YD affected human population levels: (1) frequency analyses of Paleoindian projectile points, and (2) summed probability analyses of radiocarbon (14C) dates. The results suggest that a significant decline or reorganization of human populations occurred at 12.9 ka, continued through the initial centuries of the YD chronozone, then rebounded by the end of the YD. FREQUENCY ANALYSES: This method employed projectile point data from the Paleoindian Database of the Americas (PIDBA, http://pidba.utk.edu). We tallied diagnostic projectile points and obtained larger totals for Clovis points than for immediately post-Clovis points, which share an instrument-assisted fluting technique, typically using pressure or indirect percussion. Gainey, Vail, Debert, Redstone, and Cumberland point-styles utilized this method and are comparable to the Folsom style. For the SE U.S., the ratio of Clovis points (n=1993) to post-Clovis points (n=947) reveals a point decline of 52%. For the Great Plains, a comparison of Clovis and fluted points (n=4020) to Folsom points (n=2527) shows a point decline of 37%, which may translate into a population contraction of similar magnitude. In addition, eight major Clovis lithic quarry sites in the SE U.S. exhibit little to no evidence for immediate post-Clovis occupations, implying a major population decline. SUMMED PROBABILITIES: This method involved calibrating relevant 14C dates and combining the probabilities, after which major peaks and troughs in the trends are assumed to reflect changes in human demographics. Using 14C dates from Buchanan et al. (2008), we analyzed multiple regions, including the Southeast and Great Plains. Contrary to Buchanan et al., we found an abrupt, statistically significant decline at 12.9 ka, followed 200 to 900 years later by a rebound in the number of dates. The decline at the YD onset was more than 50%, similar in magnitude to the decline in Clovis-Folsom point ratios. While calibration and sampling factors may affect the trends, this abrupt decline is large and requires explanation. SUMMARY: Even though correlation does not equate with causation, the coeval YD decline in both points and 14C dates appears linked to significant changes in climate and biota, as represented by the megafaunal extinction. While the causes of the YD remain controversial, a human population decline appears to have occurred, at least across parts of North America. Furthermore, the YD onset is associated with the abrupt replacement of Clovis by regional or subregional scale cultural traditions, potentially reflecting decreased range mobility and increased population isolation. Projectile point distributions and summed probability analyses, we argue, are potentially useful approaches for exploring demographic changes at regional scales.

Using CForest to Analyze Diffusion Tensor Imaging Data: A Study of White Matter Integrity in Healthy Aging.

PubMed

McWhinney, Sean R; Tremblay, Antoine; Chevalier, Thérèse M; Lim, Vanessa K; Newman, Aaron J

2016-12-01

Healthy aging has been associated with a global reduction in white matter integrity, which is thought to reflect cognitive decline. The present study aimed to investigate this reduction over a broad range of the life span, using diffusion tensor imaging analyzed with conditional inference random forest modeling (CForest). This approach is sensitive to subtle and potentially nonlinear effects over the age continuum and was used to characterize the progression of decline in greater detail than has been possible in the past. Data were collected from 45 healthy individuals ranging in age from 19 to 67 years. Fractional anisotropy (FA) was estimated using probabilistic tractography for a number of major tracts across the brain. Age coincided with a nonlinear decrease in FA, with onset beginning at ∼30 years of age and the steepest declines occurring later in life. However, several tracts showed a transient increase before this decline. The progression of decline varied by tract, with steeper but later decline occurring in more anterior tracts. Finally, strongly right-handed individuals demonstrated relatively preserved FA until more than a decade following the onset of decline of others. These results demonstrate that using a novel, nonparametric analysis approach, previously reported reductions in FA with healthy aging were confirmed, while at the same time, new insight was provided into the onset and progression of decline, with evidence suggesting increases in integrity continuing into adulthood.

Analysis of neuron–astrocyte metabolic cooperation in the brain of db/db mice with cognitive decline using 13C NMR spectroscopy

PubMed Central

Zheng, Hong; Zheng, Yongquan; Wang, Dan; Cai, Aimin; Lin, Qiuting; Zhao, Liangcai; Chen, Minjiang; Deng, Mingjie; Ye, Xinjian

2016-01-01

Type 2 diabetes has been linked to cognitive impairment, but its potential metabolic mechanism is still unclear. The present study aimed to explore neuron–astrocyte metabolic cooperation in the brain of diabetic (db/db, BKS.Cg-m+/+ Leprdb/J) mice with cognitive decline using 13C NMR technique in combination with intravenous [2-13C]-acetate and [3-13C]-lactate infusions. We found that the 13C-enrichment from [2-13C]-acetate into tricarboxylic acid cycle intermediate, succinate, was significantly decreased in db/db mice with cognitive decline compared with wild-type (WT, C57BLKS/J) mice, while an opposite result was obtained after [3-13C]-lactate infusion. Relative to WT mice, db/db mice with cognitive decline had significantly lower 13C labeling percentages in neurotransmitters including glutamine, glutamate, and γ-aminobutyric acid after [2-13C]-acetate infusion. However, [3-13C]-lactate resulted in increased 13C-enrichments in neurotransmitters in db/db mice with cognitive decline. This may indicate that the disturbance of neurotransmitter metabolism occurred during the development of cognitive decline. In addition, a reduction in 13C-labeling of lactate and an increase in gluconeogenesis were found from both labeled infusions in db/db mice with cognitive decline. Therefore, our results suggest that the development of cognitive decline in type 2 diabetes may be implicated to an unbalanced metabolism in neuron–astrocyte cooperation and an enhancement of gluconeogenesis. PMID:26762505

Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance1[C][W][OPEN

PubMed Central

Scoffoni, Christine; Vuong, Christine; Diep, Steven; Cochard, Hervé; Sack, Lawren

2014-01-01

Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conductance (Kleaf). For 14 diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell and airspace thickness, and leaf area) is associated with reduction in Kleaf at declining leaf water potential (Ψleaf). We tested hypotheses for the linkage of leaf shrinkage with structural and physiological water relations parameters, including modulus of elasticity, osmotic pressure at full turgor, turgor loss point (TLP), and cuticular conductance. Species originating from moist habitats showed substantial shrinkage during dehydration before reaching TLP, in contrast with species originating from dry habitats. Across species, the decline of Kleaf with mild dehydration (i.e. the initial slope of the Kleaf versus Ψleaf curve) correlated with the decline of leaf thickness (the slope of the leaf thickness versus Ψleaf curve), as expected based on predictions from computer simulations. Leaf thickness shrinkage before TLP correlated across species with lower modulus of elasticity and with less negative osmotic pressure at full turgor, as did leaf area shrinkage between full turgor and oven desiccation. These findings point to a role for leaf shrinkage in hydraulic decline during mild dehydration, with potential impacts on drought adaptation for cells and leaves, influencing plant ecological distributions. PMID:24306532

Associations between cognitively stimulating leisure activities, cognitive function and age-related cognitive decline.

PubMed

Ferreira, Nicola; Owen, Adrian; Mohan, Anita; Corbett, Anne; Ballard, Clive

2015-04-01

Emerging literature suggests that lifestyle factors may play an important role in reducing age-related cognitive decline. There have, however, been few studies investigating the role of cognitively stimulating leisure activities in maintaining cognitive health. This study sought to identify changes in cognitive performance with age and to investigate associations of cognitive performance with several key cognitively stimulating leisure activities. Over 65,000 participants provided demographic and lifestyle information and completed tests of grammatical reasoning, spatial working memory, verbal working memory and episodic memory. Regression analyses suggested that frequency of engaging in Sudoku or similar puzzles was significantly positively associated with grammatical reasoning, spatial working memory and episodic memory scores. Furthermore, for participants aged under 65 years, frequency of playing non-cognitive training computer games was also positively associated with performance in the same cognitive domains. The results also suggest that grammatical reasoning and episodic memory are particularly vulnerable to age-related decline. Further investigation to determine the potential benefits of participating in Sudoku puzzles and non-cognitive computer games is indicated, particularly as they are associated with grammatical reasoning and episodic memory, cognitive domains found to be strongly associated with age-related cognitive decline. Results of this study have implications for developing improved guidance for the public regarding the potential value of cognitively stimulating leisure activities. The results also suggest that grammatical reasoning and episodic memory should be targeted in developing appropriate outcome measures to assess efficacy of future interventions, and in developing cognitive training programmes to prevent or delay cognitive decline. Copyright © 2014 John Wiley & Sons, Ltd.

Leaf shrinkage with dehydration: coordination with hydraulic vulnerability and drought tolerance.

PubMed

Scoffoni, Christine; Vuong, Christine; Diep, Steven; Cochard, Hervé; Sack, Lawren

2014-04-01

Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conductance (K(leaf)). For 14 diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell and airspace thickness, and leaf area) is associated with reduction in K(leaf) at declining leaf water potential (Ψ(leaf)). We tested hypotheses for the linkage of leaf shrinkage with structural and physiological water relations parameters, including modulus of elasticity, osmotic pressure at full turgor, turgor loss point (TLP), and cuticular conductance. Species originating from moist habitats showed substantial shrinkage during dehydration before reaching TLP, in contrast with species originating from dry habitats. Across species, the decline of K(leaf) with mild dehydration (i.e. the initial slope of the K(leaf) versus Ψ(leaf) curve) correlated with the decline of leaf thickness (the slope of the leaf thickness versus Ψ(leaf) curve), as expected based on predictions from computer simulations. Leaf thickness shrinkage before TLP correlated across species with lower modulus of elasticity and with less negative osmotic pressure at full turgor, as did leaf area shrinkage between full turgor and oven desiccation. These findings point to a role for leaf shrinkage in hydraulic decline during mild dehydration, with potential impacts on drought adaptation for cells and leaves, influencing plant ecological distributions.

The Potential for Human Resources and Economic Growth in a Declining Local Community, A Socio-Economic Study of the Johnstown, Pennsylvania Economy, Volume II.

ERIC Educational Resources Information Center

Levine, Louis; And Others

The data provided in the second volume of this two-volume report are interpreted within the context of the social and economic problems identified in the first volume. With its lack of diversified industry, Johnstown, Pennsylvania was found to have the revenue problems typical of a depressed economy, accentuated by a decline in markets for its…

Ocean deoxygenation in a warming world.

PubMed

Keeling, Ralph E; Körtzinger, Arne; Gruber, Nicolas

2010-01-01

Ocean warming and increased stratification of the upper ocean caused by global climate change will likely lead to declines in dissolved O2 in the ocean interior (ocean deoxygenation) with implications for ocean productivity, nutrient cycling, carbon cycling, and marine habitat. Ocean models predict declines of 1 to 7% in the global ocean O2 inventory over the next century, with declines continuing for a thousand years or more into the future. An important consequence may be an expansion in the area and volume of so-called oxygen minimum zones, where O2 levels are too low to support many macrofauna and profound changes in biogeochemical cycling occur. Significant deoxygenation has occurred over the past 50 years in the North Pacific and tropical oceans, suggesting larger changes are looming. The potential for larger O2 declines in the future suggests the need for an improved observing system for tracking ocean 02 changes.

Functional fusion of living systems with synthetic electrode interfaces.

PubMed

Staufer, Oskar; Weber, Sebastian; Bengtson, C Peter; Bading, Hilmar; Spatz, Joachim P; Rustom, Amin

2016-01-01

The functional fusion of "living" biomaterial (such as cells) with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries "perfected" during billion years of evolution. To date, hardware-wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. Nat. Biotech. 2012, 30, 1240-1243). More recent approaches employ nanowires (NWs) able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. Nat. Nano. 2013, 8, 83-94). Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. Nat Nanotechnol. 2012, 10, 180-184) or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. Nat. Nano. 2013, 9, 142-147), vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. Nano Lett. 2007, 7, 2960-2965) or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording electrical responses from oxidative events occurring in intercellular regions of neuronal cultures (Zhang, D.; Rand, E.; Marsh, M.; Andrews, R.; Lee, K.; Meyyappan, M.; Koehne, J. Mol. Neurobiol. 2013, 48, 380-385). Employing monocrystalline gold, nanoelectrode interfaces, we have now achieved stable, functional access to the electrochemical machinery of individual Physarum polycephalum slime mold cells. We demonstrate the "symbionic" union, allowing for electrophysiological measurements, functioning as autonomous sensors and capable of producing nanowatts of electric power. This represents a further step towards the future development of groundbreaking, cell-based technologies, such as bionic sensory systems or miniaturized energy sources to power various devices, or even "intelligent implants", constantly refueled by their surrounding nutrients.

Functional fusion of living systems with synthetic electrode interfaces

PubMed Central

Staufer, Oskar; Weber, Sebastian; Bengtson, C Peter; Bading, Hilmar; Spatz, Joachim P

2016-01-01

Summary The functional fusion of “living” biomaterial (such as cells) with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries “perfected” during billion years of evolution. To date, hardware–wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. Nat. Biotech. 2012, 30, 1240–1243). More recent approaches employ nanowires (NWs) able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. Nat. Nano. 2013, 8, 83–94). Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. Nat Nanotechnol. 2012, 10, 180–184) or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. Nat. Nano. 2013, 9, 142–147), vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. Nano Lett. 2007, 7, 2960–2965) or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording electrical responses from oxidative events occurring in intercellular regions of neuronal cultures (Zhang, D.; Rand, E.; Marsh, M.; Andrews, R.; Lee, K.; Meyyappan, M.; Koehne, J. Mol. Neurobiol. 2013, 48, 380–385). Employing monocrystalline gold, nanoelectrode interfaces, we have now achieved stable, functional access to the electrochemical machinery of individual Physarum polycephalum slime mold cells. We demonstrate the “symbionic” union, allowing for electrophysiological measurements, functioning as autonomous sensors and capable of producing nanowatts of electric power. This represents a further step towards the future development of groundbreaking, cell-based technologies, such as bionic sensory systems or miniaturized energy sources to power various devices, or even “intelligent implants”, constantly refueled by their surrounding nutrients. PMID:26977386

National Decline in Donor Heart Utilization With Regional Variability: 1995–2010

PubMed Central

Khush, K. K.; Zaroff, J. G.; Nguyen, J.; Menza, R.; Goldstein, B. A.

2015-01-01

The severe shortage of donor hearts limits the availability of transplantation for the growing population of patients with end-stage heart disease. We examined national trends in donor heart acceptance for transplant. OPTN data were analyzed for all potential adult cardiac organ donors between 1995 and 2010. Donor heart disposition was categorized as transplanted, declined for transplant or other. We studied changes in the probability of donor heart acceptance according to demographic and clinical characteristics, nationwide and by UNOS region. Of 82 053 potential donor hearts, 34% were accepted and 48% were declined (18% used for other purposes). There was a significant decrease in donor heart acceptance from 44% in 1995 to 29% in 2006, and subsequent increase to 32% in 2010. Older donor age, female sex and medical co-morbidities predicted non-acceptance. Donor age and co-morbidities increased during the study period, with a concomitant decrease in acceptance of hearts from donors with undesirable characteristics. Overall, predictors of heart non-use were similar across UNOS regions, although utilization varied between regions. Regional variation suggests a potential to improve heart acceptance rates in under-performing regions, and supports research and policy efforts aimed at establishing evidence-based criteria for donor heart evaluation and acceptance for transplantation. PMID:25676093

The Potential for Spatial Distribution Indices to Signal Thresholds in Marine Fish Biomass

PubMed Central

Reuchlin-Hugenholtz, Emilie

2015-01-01

The frequently observed positive relationship between fish population abundance and spatial distribution suggests that changes in distribution can be indicative of trends in abundance. If contractions in spatial distribution precede declines in spawning stock biomass (SSB), spatial distribution reference points could complement the SSB reference points that are commonly used in marine conservation biology and fisheries management. When relevant spatial distribution information is integrated into fisheries management and recovery plans, risks and uncertainties associated with a plan based solely on the SSB criterion would be reduced. To assess the added value of spatial distribution data, we examine the relationship between SSB and four metrics of spatial distribution intended to reflect changes in population range, concentration, and density for 10 demersal populations (9 species) inhabiting the Scotian Shelf, Northwest Atlantic. Our primary purpose is to assess their potential to serve as indices of SSB, using fisheries independent survey data. We find that metrics of density offer the best correlate of spawner biomass. A decline in the frequency of encountering high density areas is associated with, and in a few cases preceded by, rapid declines in SSB in 6 of 10 populations. Density-based indices have considerable potential to serve both as an indicator of SSB and as spatially based reference points in fisheries management. PMID:25789624

Higher Sensitivity in X-Ray Photography

NASA Technical Reports Server (NTRS)

Buggle, R. N.

1986-01-01

Hidden defects revealed if X-ray energy decreased as exposure progresses. Declining-potential X-ray photography detects fractures in thin metal sheet covered by unbroken sheet of twice thickness. Originally developed to check solder connections on multilayer circuit boards, technique has potential for other nondestructive testing.

Projected Scenarios for Coastal First Nations' Fisheries Catch Potential under Climate Change: Management Challenges and Opportunities.

PubMed

Weatherdon, Lauren V; Ota, Yoshitaka; Jones, Miranda C; Close, David A; Cheung, William W L

2016-01-01

Studies have demonstrated ways in which climate-related shifts in the distributions and relative abundances of marine species are expected to alter the dynamics and catch potential of global fisheries. While these studies assess impacts on large-scale commercial fisheries, few efforts have been made to quantitatively project impacts on small-scale subsistence and commercial fisheries that are economically, socially and culturally important to many coastal communities. This study uses a dynamic bioclimate envelope model to project scenarios of climate-related changes in the relative abundance, distribution and richness of 98 exploited marine fishes and invertebrates of commercial and cultural importance to First Nations in coastal British Columbia, Canada. Declines in abundance are projected for most of the sampled species under both the lower (Representative Concentration Pathway [RCP] 2.6) and higher (RCP 8.5) emission scenarios (-15.0% to -20.8%, respectively), with poleward range shifts occurring at a median rate of 10.3 to 18.0 km decade(-1) by 2050 relative to 2000. While a cumulative decline in catch potential is projected coastwide (-4.5 to -10.7%), estimates suggest a strong positive correlation between the change in relative catch potential and latitude, with First Nations' territories along the northern and central coasts of British Columbia likely to experience less severe declines than those to the south. Furthermore, a strong negative correlation is projected between latitude and the number of species exhibiting declining abundance. These trends are shown to be robust to alternative species distribution models. This study concludes by discussing corresponding management challenges that are likely to be encountered under climate change, and by highlighting the value of joint-management frameworks and traditional fisheries management approaches that could aid in offsetting impacts and developing site-specific mitigation and adaptation strategies derived from local fishers' knowledge.

Vulnerability of the Great Barrier Reef to climate change and local pressures.

PubMed

Wolff, Nicholas H; Mumby, Peter J; Devlin, Michelle; Anthony, Kenneth R N

2018-05-01

Australia's Great Barrier Reef (GBR) is under pressure from a suite of stressors including cyclones, crown-of-thorns starfish (COTS), nutrients from river run-off and warming events that drive mass coral bleaching. Two key questions are: how vulnerable will the GBR be to future environmental scenarios, and to what extent can local management actions lower vulnerability in the face of climate change? To address these questions, we use a simple empirical and mechanistic coral model to explore six scenarios that represent plausible combinations of climate change projections (from four Representative Concentration Pathways, RCPs), cyclones and local stressors. Projections (2017-2050) indicate significant potential for coral recovery in the near-term, relative to current state, followed by climate-driven decline. Under a scenario of unmitigated emissions (RCP8.5) and business-as-usual management of local stressors, mean coral cover on the GBR is predicted to recover over the next decade and then rapidly decline to only 3% by year 2050. In contrast, a scenario of strong carbon mitigation (RCP2.6) and improved water quality, predicts significant coral recovery over the next two decades, followed by a relatively modest climate-driven decline that sustained coral cover above 26% by 2050. In an analysis of the impacts of cumulative stressors on coral cover relative to potential coral cover in the absence of such impacts, we found that GBR-wide reef performance will decline 27%-74% depending on the scenario. Up to 66% of performance loss is attributable to local stressors. The potential for management to reduce vulnerability, measured here as the mean number of years coral cover can be kept above 30%, is spatially variable. Management strategies that alleviate cumulative impacts have the potential to reduce the vulnerability of some midshelf reefs in the central GBR by 83%, but only if combined with strong mitigation of carbon emissions. © 2018 John Wiley & Sons Ltd.

Projected Scenarios for Coastal First Nations’ Fisheries Catch Potential under Climate Change: Management Challenges and Opportunities

PubMed Central

Weatherdon, Lauren V.; Ota, Yoshitaka; Jones, Miranda C.; Close, David A.; Cheung, William W. L.

2016-01-01

Studies have demonstrated ways in which climate-related shifts in the distributions and relative abundances of marine species are expected to alter the dynamics and catch potential of global fisheries. While these studies assess impacts on large-scale commercial fisheries, few efforts have been made to quantitatively project impacts on small-scale subsistence and commercial fisheries that are economically, socially and culturally important to many coastal communities. This study uses a dynamic bioclimate envelope model to project scenarios of climate-related changes in the relative abundance, distribution and richness of 98 exploited marine fishes and invertebrates of commercial and cultural importance to First Nations in coastal British Columbia, Canada. Declines in abundance are projected for most of the sampled species under both the lower (Representative Concentration Pathway [RCP] 2.6) and higher (RCP 8.5) emission scenarios (-15.0% to -20.8%, respectively), with poleward range shifts occurring at a median rate of 10.3 to 18.0 km decade-1 by 2050 relative to 2000. While a cumulative decline in catch potential is projected coastwide (-4.5 to -10.7%), estimates suggest a strong positive correlation between the change in relative catch potential and latitude, with First Nations’ territories along the northern and central coasts of British Columbia likely to experience less severe declines than those to the south. Furthermore, a strong negative correlation is projected between latitude and the number of species exhibiting declining abundance. These trends are shown to be robust to alternative species distribution models. This study concludes by discussing corresponding management challenges that are likely to be encountered under climate change, and by highlighting the value of joint-management frameworks and traditional fisheries management approaches that could aid in offsetting impacts and developing site-specific mitigation and adaptation strategies derived from local fishers’ knowledge. PMID:26761439

Factors influencing the decline in stroke mortality: a statement from the American Heart Association/American Stroke Association.

PubMed

Lackland, Daniel T; Roccella, Edward J; Deutsch, Anne F; Fornage, Myriam; George, Mary G; Howard, George; Kissela, Brett M; Kittner, Steven J; Lichtman, Judith H; Lisabeth, Lynda D; Schwamm, Lee H; Smith, Eric E; Towfighi, Amytis

2014-01-01

Stroke mortality has been declining since the early 20th century. The reasons for this are not completely understood, although the decline is welcome. As a result of recent striking and more accelerated decreases in stroke mortality, stroke has fallen from the third to the fourth leading cause of death in the United States. This has prompted a detailed assessment of the factors associated with the change in stroke risk and mortality. This statement considers the evidence for factors that have contributed to the decline and how they can be used in the design of future interventions for this major public health burden. Writing group members were nominated by the committee chair and co-chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council's Scientific Statements Oversight Committee and the American Heart Association Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiological studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize evidence and to indicate gaps in current knowledge. All members of the writing group had the opportunity to comment on this document and approved the final version. The document underwent extensive American Heart Association internal peer review, Stroke Council leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee. The decline in stroke mortality over the past decades represents a major improvement in population health and is observed for both sexes and for all racial/ethnic and age groups. In addition to the overall impact on fewer lives lost to stroke, the major decline in stroke mortality seen among people <65 years of age represents a reduction in years of potential life lost. The decline in mortality results from reduced incidence of stroke and lower case-fatality rates. These significant improvements in stroke outcomes are concurrent with cardiovascular risk factor control interventions. Although it is difficult to calculate specific attributable risk estimates, efforts in hypertension control initiated in the 1970s appear to have had the most substantial influence on the accelerated decline in stroke mortality. Although implemented later, diabetes mellitus and dyslipidemia control and smoking cessation programs, particularly in combination with treatment of hypertension, also appear to have contributed to the decline in stroke mortality. The potential effects of telemedicine and stroke systems of care appear to be strong but have not been in place long enough to indicate their influence on the decline. Other factors had probable effects, but additional studies are needed to determine their contributions. The decline in stroke mortality is real and represents a major public health and clinical medicine success story. The repositioning of stroke from third to fourth leading cause of death is the result of true mortality decline and not an increase in mortality from chronic lung disease, which is now the third leading cause of death in the United States. There is strong evidence that the decline can be attributed to a combination of interventions and programs based on scientific findings and implemented with the purpose of reducing stroke risks, the most likely being improved control of hypertension. Thus, research studies and the application of their findings in developing intervention programs have improved the health of the population. The continued application of aggressive evidence-based public health programs and clinical interventions is expected to result in further declines in stroke mortality.

Assessing the links among environmental contaminants, endocrinology, and parasites to understand amphibian declines in montane regions of Costa Rica

PubMed Central

Ralicki, Hannah F.; Laurencio, David; Crocker-Buta, Sarah

2018-01-01

Amphibians inhabiting montane riparian zones in the Neotropics are particularly vulnerable to decline, but the reasons are poorly understood. Because environmental contaminants, endocrine disruption, and pathogens often figure prominently in amphibian declines it is imperative that we understand how these factors are potentially interrelated to affect montane populations. One possibility is that increased precipitation associated with global warming promotes the deposition of contaminants in montane regions. Increased exposure to contaminants, in turn, potentially elicits chronic elevations in circulating stress hormones that could contribute to montane population declines by compromising resistance to pathogens and/or production of sex steroids regulating reproduction. Here, we test this hypothesis by examining contaminant levels, stress and sex steroid levels, and nematode abundances in male drab treefrogs, Smilisca sordida, from lowland and montane populations in Costa Rica. We found no evidence that montane populations were more likely to possess contaminants (i.e., organochlorine, organophosphate and carbamate pesticides or benzidine and chlorophenoxy herbicides) than lowland populations. We also found no evidence of elevational differences in circulating levels of the stress hormone corticosterone, estradiol or progesterone. However, montane populations possessed lower androgen levels, hosted more nematode species, and had higher nematode abundances than lowland populations. Although these results suggested that nematodes contributed to lower androgens in montane populations, we were unable to detect a significant inverse relationship between nematode abundance and androgen level. Our results suggest that montane populations of this species are not at greater risk of exposure to contaminants or chronic stress, but implicate nematodes and compromised sex steroid levels as potential threats to montane populations. PMID:29324824

Hydrogeology and potential effects of changes in water use, Carson Desert agricultural area, Churchill County, Nevada

USGS Publications Warehouse

Maurer, Douglas K.; Johnson, Ann K.; Welch, Alan H.

1996-01-01

Operating Criteria and Procedures for Newlands Project irrigation and Public Law 101-618 could result in reductions in surface water used for agriculture in the Carson Desert, potentially affecting ground-water supplies from shallow, intermediate, and basalt aquifers. A near-surface zone could exist at the top of the shallow aquifer near the center and eastern parts of the basin where underlying clay beds inhibit vertical flow and could limit the effects of changes in water use. In the basalt aquifer, water levels have declined about 10 feet from pre-pumping levels, and chloride and arsenic concentrations have increased. Conceptual models of the basin suggest that changes in water use in the western part of the basin would probably affect recharge to the shallow, intermediate, and basalt aquifers. Lining canals and removing land from production could cause water-level declines greater than 10 feet in the shallow aquifer up to 2 miles from lined canals. Removing land from production could cause water levels to decline from 4 to 17 feet, depending on the distribution of specific yield in the basin and the amount of water presently applied to irrigated fields. Where wells pump from a near-surface zone of the shallow aquifer, water level declines might not greatly affect pumping wells where the thickness of the zone is greatest, but could cause wells to go dry where the zone is thin.

Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines.

PubMed

Regehr, Eric V; Laidre, Kristin L; Akçakaya, H Resit; Amstrup, Steven C; Atwood, Todd C; Lunn, Nicholas J; Obbard, Martyn; Stern, Harry; Thiemann, Gregory W; Wiig, Øystein

2016-12-01

Loss of Arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. We evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (GL) for the species, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approaches relating polar bear abundance to sea ice. Mean GL was 11.5 years. Ice-covered days declined in all subpopulation areas during 1979-2014 (median -1.26 days year -1 ). The estimated probabilities that reductions in the mean global population size of polar bears will be greater than 30%, 50% and 80% over three generations (35-41 years) were 0.71 (range 0.20-0.95), 0.07 (range 0-0.35) and less than 0.01 (range 0-0.02), respectively. According to IUCN Red List reduction thresholds, which provide a common measure of extinction risk across taxa, these results are consistent with listing the species as vulnerable. Our findings support the potential for large declines in polar bear numbers owing to sea-ice loss, and highlight near-term uncertainty in statistical projections as well as the sensitivity of projections to different plausible assumptions. © 2016 The Authors.

The therapeutic potential of metabolic hormones in the treatment of age-related cognitive decline and Alzheimer’s disease

PubMed Central

Grizzanti, John; Lee, Hyoung-Gon; Camins, Antoni; Pallas, Merce; Casadesus, Gemma

2017-01-01

Aging leads to a number of physiological alterations, specifically changes in circulating hormone levels, increases in fat deposition, decreases in metabolism, changes in inflammatory responses, and reductions in growth factors. These progressive changes in physiology and metabolism are exacerbated by modern culture and Western diet and give rise to diseases such as obesity, metabolic syndrome, and type 2 (non–insulin-dependent) diabetes (T2D). These age and lifestyle-related metabolic diseases are often accompanied by insulin and leptin resistance, as well as aberrant amylin production and signaling. Many of these alterations in hormone production and signaling are directly influenced by an increase in both oxidative stress and inflammation. Importantly, changes in hormone production and signaling have direct effects on brain function and the development of age-related neurologic disorders. Therefore, this review aims to present evidence on the effects that diet and metabolic disease have on age-related cognitive decline and the development of cognitive diseases, particularly Alzheimer disease. This review will focus on the metabolic hormones insulin, leptin, and amylin and their role in cognitive decline, as well as the therapeutic potential of these hormones in treating cognitive disease. Future investigations targeting the long-term effects of insulin and leptin treatment may reveal evidence to reduce risk of cognitive decline and Alzheimer disease. PMID:27923524

Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines

USGS Publications Warehouse

Regehr, Eric V.; Laidre, Kristin L.; Akçakaya, H. Resit; Amstrup, Steven C.; Atwood, Todd C.; Lunn, Nicholas J.; Obbard, Martyn E.; Stern, Harry; Thiemann, Gregory W.; Wiig, Øystein

2016-01-01

Loss of Arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. We evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (GL) for the species, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approaches relating polar bear abundance to sea ice. Mean GL was 11.5 years. Ice-covered days declined in all subpopulation areas during 1979–2014 (median −1.26 days year−1). The estimated probabilities that reductions in the mean global population size of polar bears will be greater than 30%, 50% and 80% over three generations (35–41 years) were 0.71 (range 0.20–0.95), 0.07 (range 0–0.35) and less than 0.01 (range 0–0.02), respectively. According to IUCN Red List reduction thresholds, which provide a common measure of extinction risk across taxa, these results are consistent with listing the species as vulnerable. Our findings support the potential for large declines in polar bear numbers owing to sea-ice loss, and highlight near-term uncertainty in statistical projections as well as the sensitivity of projections to different plausible assumptions.

The Aging Mind: Potential and Limits.

ERIC Educational Resources Information Center

Baltes, Paul B.

1993-01-01

Notes that research on aging mind has moved from simple growth versus decline view to conception of joint consideration of potential and limits. Sees this development illustrated by research on two categories of cognitive functioning: the cognitive mechanics (comparable to fluid intelligence) and cognitive pragmatics (comparable to crystallized…

Big city Bombus: using natural history and land-use history to find significant environmental drivers in bumble-bee declines in urban development.

PubMed

Glaum, Paul; Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin

2017-05-01

Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee ( Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that 'shrinking cities' potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation.

Big city Bombus: using natural history and land-use history to find significant environmental drivers in bumble-bee declines in urban development

PubMed Central

Simao, Maria-Carolina; Vaidya, Chatura; Fitch, Gordon; Iulinao, Benjamin

2017-01-01

Native bee populations are critical sources of pollination. Unfortunately, native bees are declining in abundance and diversity. Much of this decline comes from human land-use change. While the effects of large-scale agriculture on native bees are relatively well understood, the effects of urban development are less clear. Understanding urbanity's effect on native bees requires consideration of specific characteristics of both particular bee species and their urban landscape. We surveyed bumble-bee (Bombus spp.) abundance and diversity in gardens across multiple urban centres in southeastern Michigan. There are significant declines in Bombus abundance and diversity associated with urban development when measured on scales in-line with Bombus flight ability. These declines are entirely driven by declines in females; males showed no response to urbanization. We hypothesize that this is owing to differing foraging strategies between the sexes, and it suggests reduced Bombus colony density in more urban areas. While urbanity reduced Bombus prevalence, results in Detroit imply that ‘shrinking cities’ potentially offer unique urban paradigms that must be considered when studying wild bee ecology. Results show previously unidentified differences in the effects of urbanity on female and male bumble-bee populations and suggest that urban landscapes can be managed to support native bee conservation. PMID:28573023

Analysis of neuron-astrocyte metabolic cooperation in the brain of db/db mice with cognitive decline using 13C NMR spectroscopy.

PubMed

Zheng, Hong; Zheng, Yongquan; Wang, Dan; Cai, Aimin; Lin, Qiuting; Zhao, Liangcai; Chen, Minjiang; Deng, Mingjie; Ye, Xinjian; Gao, Hongchang

2017-01-01

Type 2 diabetes has been linked to cognitive impairment, but its potential metabolic mechanism is still unclear. The present study aimed to explore neuron-astrocyte metabolic cooperation in the brain of diabetic (db/db, BKS.Cg-m +/+ Leprdb/J) mice with cognitive decline using 13 C NMR technique in combination with intravenous [2- 13 C]-acetate and [3- 13 C]-lactate infusions. We found that the 13 C-enrichment from [2- 13 C]-acetate into tricarboxylic acid cycle intermediate, succinate, was significantly decreased in db/db mice with cognitive decline compared with wild-type (WT, C57BLKS/J) mice, while an opposite result was obtained after [3- 13 C]-lactate infusion. Relative to WT mice, db/db mice with cognitive decline had significantly lower 13 C labeling percentages in neurotransmitters including glutamine, glutamate, and γ-aminobutyric acid after [2- 13 C]-acetate infusion. However, [3- 13 C]-lactate resulted in increased 13 C-enrichments in neurotransmitters in db/db mice with cognitive decline. This may indicate that the disturbance of neurotransmitter metabolism occurred during the development of cognitive decline. In addition, a reduction in 13 C-labeling of lactate and an increase in gluconeogenesis were found from both labeled infusions in db/db mice with cognitive decline. Therefore, our results suggest that the development of cognitive decline in type 2 diabetes may be implicated to an unbalanced metabolism in neuron-astrocyte cooperation and an enhancement of gluconeogenesis. © The Author(s) 2016.

Dietary habits of polar bears in Foxe Basin, Canada: possible evidence of a trophic regime shift mediated by a new top predator.

PubMed

Galicia, Melissa P; Thiemann, Gregory W; Dyck, Markus G; Ferguson, Steven H; Higdon, Jeff W

2016-08-01

Polar bear (Ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. In the Foxe Basin region of Nunavut, Canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. We used fatty acid analysis to examine polar bear feeding habits in Foxe Basin and thus potentially identify ecological factors contributing to population stability. Adipose tissue samples were collected from 103 polar bears harvested during 2010-2012. Polar bear diet composition varied spatially within the region with ringed seal (Pusa hispida) comprising the primary prey in northern and southern Foxe Basin, whereas polar bears in Hudson Strait consumed equal proportions of ringed seal and harp seal (Pagophilus groenlandicus). Walrus (Odobenus rosmarus) consumption was highest in northern Foxe Basin, a trend driven by the ability of adult male bears to capture large-bodied prey. Importantly, bowhead whale (Balaena mysticetus) contributed to polar bear diets in all areas and all age and sex classes. Bowhead carcasses resulting from killer whale (Orcinus orca) predation and subsistence harvest potentially provide an important supplementary food source for polar bears during the ice-free period. Our results suggest that the increasing abundance of killer whales and bowhead whales in the region could be indirectly contributing to improved polar bear foraging success despite declining sea ice habitat. However, this indirect interaction between top predators may be temporary if continued sea ice declines eventually severely limit on-ice feeding opportunities for polar bears.

Physical Exercise-Induced Adult Neurogenesis: A Good Strategy to Prevent Cognitive Decline in Neurodegenerative Diseases?

PubMed Central

Yau, Suk-yu; Christie, Brian R.; So, Kwok-fai

2014-01-01

Cumulative evidence has indicated that there is an important role for adult hippocampal neurogenesis in cognitive function. With the increasing prevalence of cognitive decline associated with neurodegenerative diseases among the ageing population, physical exercise, a potent enhancer of adult hippocampal neurogenesis, has emerged as a potential preventative strategy/treatment to reduce cognitive decline. Here we review the functional role of adult hippocampal neurogenesis in learning and memory, and how this form of structural plasticity is altered in neurodegenerative diseases known to involve cognitive impairment. We further discuss how physical exercise may contribute to cognitive improvement in the ageing brain by preserving adult neurogenesis, and review the recent approaches for measuring changes in neurogenesis in the live human brain. PMID:24818140

Potential for nest site competition between native and exotic tree squirrels

Treesearch

Andrew J. Edelman; John L. Koprowski; Sadie R. Bertelsen

2009-01-01

In communities where strong interspecific competition between native species is lacking, exotic and native species often exhibit intense resource competition resulting in decline of native populations. We examined the potential for interspecific competition for nest sites between co-occurring native Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis...

Potential sea-level rise impacts on tidal wetlands in the Pacific Northwest: Declines in productivity and diversity?

EPA Science Inventory

Global climate change could alter sea-level and salinity dynamics in Pacific Northwest estuaries. We combined survey and experimental approaches to better understand potential climate change effects on the future of tidal wetland primary producers in the region. Surveys conducte...

Early decline in glucose transport and metabolism precedes shift to ketogenic system in female aging and Alzheimer's mouse brain: implication for bioenergetic intervention.

PubMed

Ding, Fan; Yao, Jia; Rettberg, Jamaica R; Chen, Shuhua; Brinton, Roberta Diaz

2013-01-01

We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3-15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6-9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential targets for preventing shifts to less efficient bioenergetic fuels and transition to the ketogenic phenotype of the Alzheimer's brain.

Integrated fault seal analysis and risk assessemt: Okan and Meren Fields, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisenberg, R.A.; Brenneman, R.J.; Adepoju, A.A.

1996-01-01

Integration of production, geochemical, seismic, well log, and structural data provides important constraints on the sealing capacity and dynamic behavior of fault juxtaposed reservoirs in Okan and Meren fields, offshore Nigeria. Correlations were found between pressure decline histories, juxtaposed fluid types, oil composition, fluid contact relationships, fault sealing/leaking condition, and estimates of the composition of the fault gouge. Fault plane sections defined reservoir juxtapositions and potential cross-fault spill points. Smear gouge ratios calculated from E-logs were used to estimate the composition of fault-gouge materials between juxtaposed reservoirs. These tools augmented interpretation of seal/nonseal character in proved reservoirs and were usedmore » to quantify fault seal risk of untested, fault-dependent closures. In the Okan Field juxtapositions of the G-, H, L-, M, and O-sands were analyzed. Smear gouge ratios correlated to fluid contact relationships and pressure decline histories within these juxtaposed reservoirs empirically calibrate sealing potential. The results of these analyses were then used to interpret production-induced fault seal breakdown within the G-sands and to risk seal integrity of fault-dependent closures within the untested 0-sands in an adjacent, upthrown fault block. Within this fault block the presence of potential fault intersection leak points and large areas of sand/sand juxtaposition with high smear gouge ratios (low sealing potential) limits column heights and potential reserves within the O-sand package. In the Meren Field the E- and G-sands are juxtaposed, on different pressure decline, geochemically distinct, and are characterized by low smear gouge ratios. In contrast, the G- and H-sands, juxtaposed across the same fault, contain similar OOWCs and are characterized by high smear gouge ratios.« less

Integrated fault seal analysis and risk assessemt: Okan and Meren Fields, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisenberg, R.A.; Brenneman, R.J.; Adepoju, A.A.

Integration of production, geochemical, seismic, well log, and structural data provides important constraints on the sealing capacity and dynamic behavior of fault juxtaposed reservoirs in Okan and Meren fields, offshore Nigeria. Correlations were found between pressure decline histories, juxtaposed fluid types, oil composition, fluid contact relationships, fault sealing/leaking condition, and estimates of the composition of the fault gouge. Fault plane sections defined reservoir juxtapositions and potential cross-fault spill points. Smear gouge ratios calculated from E-logs were used to estimate the composition of fault-gouge materials between juxtaposed reservoirs. These tools augmented interpretation of seal/nonseal character in proved reservoirs and were usedmore » to quantify fault seal risk of untested, fault-dependent closures. In the Okan Field juxtapositions of the G-, H, L-, M, and O-sands were analyzed. Smear gouge ratios correlated to fluid contact relationships and pressure decline histories within these juxtaposed reservoirs empirically calibrate sealing potential. The results of these analyses were then used to interpret production-induced fault seal breakdown within the G-sands and to risk seal integrity of fault-dependent closures within the untested 0-sands in an adjacent, upthrown fault block. Within this fault block the presence of potential fault intersection leak points and large areas of sand/sand juxtaposition with high smear gouge ratios (low sealing potential) limits column heights and potential reserves within the O-sand package. In the Meren Field the E- and G-sands are juxtaposed, on different pressure decline, geochemically distinct, and are characterized by low smear gouge ratios. In contrast, the G- and H-sands, juxtaposed across the same fault, contain similar OOWCs and are characterized by high smear gouge ratios.« less

Commentary on: Subjective cognitive decline is longitudinally associated with lower health-related quality of life.

PubMed

Cooper, Claudia

2017-12-01

Public campaigns to encourage early detection of dementia in the developed world have led to identification of more people with mild cognitive impairment (MCI) or subjective cognitive decline (SCD). Early dementia diagnosis enables earlier information and support, including symptomatic treatments where appropriate. In clinical trials, detection of those with "prodromal dementia," identified from cognitive symptoms and stratified by biomarkers (Schneider, 2010), enables potential disease modifying treatments to be targeted early in the disease process, where success is more likely.

Warming delays autumn declines in photosynthetic capacity in a boreal conifer, Norway spruce (Picea abies).

PubMed

Stinziano, Joseph R; Hüner, Norman P A; Way, Danielle A

2015-12-01

Climate change, via warmer springs and autumns, may lengthen the carbon uptake period of boreal tree species, increasing the potential for carbon sequestration in boreal forests, which could help slow climate change. However, if other seasonal cues such as photoperiod dictate when photosynthetic capacity declines, warmer autumn temperatures may have little effect on when carbon uptake capacity decreases in these species. We investigated whether autumn warming would delay photosynthetic decline in Norway spruce (Picea abies (L.) H. Karst.) by growing seedlings under declining weekly photoperiods and weekly temperatures either at ambient temperature or a warming treatment 4 °C above ambient. Photosynthetic capacity was relatively constant in both treatments when weekly temperatures were >8 °C, but declined rapidly at lower temperatures, leading to a delay in the autumn decline in photosynthetic capacity in the warming treatment. The decline in photosynthetic capacity was not related to changes in leaf nitrogen or chlorophyll concentrations, but was correlated with a decrease in the apparent fraction of leaf nitrogen invested in Rubisco, implicating a shift in nitrogen allocation away from the Calvin cycle at low autumn growing temperatures. Our data suggest that as the climate warms, the period of net carbon uptake will be extended in the autumn for boreal forests dominated by Norway spruce, which could increase total carbon uptake in these forests. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Differential rate in decline in ovarian reserve markers in women with polycystic ovary syndrome compared with control subjects: results of a longitudinal study.

PubMed

Ahmad, Asima K; Kao, Chia-Ning; Quinn, Molly; Lenhart, Nikolaus; Rosen, Mitchell; Cedars, Marcelle I; Huddleston, Heather

2018-03-01

To estimate rates of ovarian aging in polycystic ovary syndrome (PCOS) subjects versus a community control population. Longitudinal. Tertiary academic center. PCOS subjects diagnosed according to the 2004 Rotterdam criteria were systematically enrolled in a PCOS cohort study. The comparison control subjects were from the Ovarian Aging study, a prospective longitudinal study of ovarian aging in healthy women with regular menstrual cycles. Clinical data collection over two study visits. Antral follicle count (AFC), ovarian volume (OV), and antimüllerian hormone level (AMH). PCOS subjects were found to have higher baseline values for all ovarian reserve markers compared with control subjects. Univariate models indicated that, compared with control subjects, PCOS patients experienced significantly faster rates of decline for both AFC and AMH. Change in OV did not differ significantly. To account for potential confounder effects, multiple analysis of covariance models were evaluated for the best fit, considering age, body mass index, and baseline ovarian reserve markers. Adjusted models demonstrated that PCOS patients do not experience a significant difference in AFC decline compared with control subjects, but they do experience a faster rate of decline in AMH (P<.01) and slower rate of decline in OV (P<.01). Ovarian aging in PCOS is characterized by a more rapid decline in AMH and a slower decline in OV compared with control subjects. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Kidney function and cognitive decline in an oldest-old Chinese population.

PubMed

Bai, Kunhao; Pan, Yujing; Lu, Fanghong; Zhao, Yingxin; Wang, Jinwei; Zhang, Luxia

2017-01-01

Early-stage chronic kidney disease has been suggested to be correlated with cognitive decline, but the association has rarely been explored in the oldest old. This prospective study included 284 Chinese participants aged 80 years or older with serum creatinine levels <150 µmol/L. The median follow-up time was 3.3 years, and 247 (87.0%) participants provided valid data at their last visit. Kidney function was evaluated by measuring the estimated glomerular filtration rate (eGFR) at baseline, and cognitive function was evaluated using the Mini-Mental State Examination (MMSE) at both baseline and annual visits. A reliable decrease in the MMSE score over the follow-up period was observed based on a Reliable Change Index of 1.645 (equivalent to a 90% confidence interval [CI]), which was used to define cognitive decline. Poisson regression models were built to analyze the association between baseline kidney function and cognitive decline. A total of 18 (7.3%) cases of incident cognitive decline were observed during the follow-up period. After adjusting for potential confounders, the relative risk of developing cognitive decline was 4.03 (95% CI 1.09-13.81) among participants with an eGFR of 30-59 mL/min/1.73 m 2 compared to participants with an eGFR of ≥60 mL/min/1.73 m 2 . Early-stage chronic kidney disease was correlated with cognitive decline in an oldest-old Chinese population.

Contrasting dynamics of leaf potential and gas exchange during progressive drought cycles and recovery in Amorpha fruticosa and Robinia pseudoacacia.

PubMed

Yan, Weiming; Zheng, Shuxia; Zhong, Yangquanwei; Shangguan, Zhouping

2017-06-30

Leaf gas exchange is closely associated with water relations; however, less attention has been given to this relationship over successive drought events. Dynamic changes in gas exchange and water potential in the seedlings of two woody species, Amorpha fruticosa and Robinia pseudoacacia, were monitored during recurrent drought. The pre-dawn leaf water potential declined in parallel with gas exchange in both species, and sharp declines in gas exchange occurred with decreasing water potential. A significant correlation between pre-dawn water potential and gas exchange was observed in both species and showed a right shift in R. pseudoacacia in the second drought. The results suggested that stomatal closure in early drought was mediated mainly by elevated foliar abscisic acid (ABA) in R. pseudoacacia, while a shift from ABA-regulated to leaf-water-potential-driven stomatal closure was observed in A. fruticosa. After re-watering, the pre-dawn water potential recovered quickly, whereas stomatal conductance did not fully recover from drought in R. pseudoacacia, which affected the ability to tightly control transpiration post-drought. The dynamics of recovery from drought suggest that stomatal behavior post-drought may be restricted mainly by hydraulic factors, but non-hydraulic factors may also be involved in R. pseudoacacia.

Characterizing changes in streamflow and sediment supply in the Sacramento River Basin, California, using hydrological simulation program—FORTRAN (HSPF)

USGS Publications Warehouse

Stern, Michelle A.; Flint, Lorraine E.; Minear, Justin T.; Flint, Alan L.; Wright, Scott A.

2016-01-01

A daily watershed model of the Sacramento River Basin of northern California was developed to simulate streamflow and suspended sediment transport to the San Francisco Bay-Delta. To compensate for sparse data, a unique combination of model inputs was developed, including meteorological variables, potential evapotranspiration, and parameters defining hydraulic geometry. A slight decreasing trend of sediment loads and concentrations was statistically significant in the lowest 50% of flows, supporting the observed historical sediment decline. Historical changes in climate, including seasonality and decline of snowpack, contribute to changes in streamflow, and are a significant component describing the mechanisms responsible for the decline in sediment. Several wet and dry hypothetical climate change scenarios with temperature changes of 1.5 °C and 4.5 °C were applied to the base historical conditions to assess the model sensitivity of streamflow and sediment to changes in climate. Of the scenarios evaluated, sediment discharge for the Sacramento River Basin increased the most with increased storm magnitude and frequency and decreased the most with increases in air temperature, regardless of changes in precipitation. The model will be used to develop projections of potential hydrologic and sediment trends to the Bay-Delta in response to potential future climate scenarios, which will help assess the hydrological and ecological health of the Bay-Delta into the next century.

Monarch butterfly population decline in North America: identifying the threatening processes

USGS Publications Warehouse

Thogmartin, Wayne E.; Wiederholt, Ruscena; Oberhauser, Karen; Drum, Ryan G.; Diffendorfer, Jay E.; Altizer, Sonia; Taylor, Orley R.; Pleasants, John M.; Semmens, Darius J.; Semmens, Brice X.; Erickson, Richard A.; Libby, Kaitlin; Lopez-Hoffman, Laura

2017-01-01

The monarch butterfly (Danaus plexippus) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.

Reconciling findings on the employment effect of disability insurance.

PubMed

Bound, John; Lindner, Stephan; Waidmann, Timothy

2014-12-01

Over the last 25 years, the Social Security Disability Insurance Program (DI) has grown dramatically. During the same period, employment rates for men with work limitations showed substantial declines in both absolute and relative terms. While the timing of these trends suggests that the expansion of DI was a major contributor to employment decline among this group, raising questions about the targeting of disability benefits, studies using denied applicants suggest a more modest role of the DI expansion. To reconcile these findings, we decompose total employment changes into population and employment changes for three categories: DI beneficiaries, denied applicants, and non-applicants. Our results show that during the early 1990s, the growth in DI can fully explain the employment decline for men only under an extreme assumption about the employment potential of beneficiaries. For the period after the mid-1990s, we find little role for the DI program in explaining the continuing employment decline for men with work limitations.

Reconciling findings on the employment effect of disability insurance

PubMed Central

Bound, John; Lindner, Stephan; Waidmann, Timothy

2016-01-01

Over the last 25 years, the Social Security Disability Insurance Program (DI) has grown dramatically. During the same period, employment rates for men with work limitations showed substantial declines in both absolute and relative terms. While the timing of these trends suggests that the expansion of DI was a major contributor to employment decline among this group, raising questions about the targeting of disability benefits, studies using denied applicants suggest a more modest role of the DI expansion. To reconcile these findings, we decompose total employment changes into population and employment changes for three categories: DI beneficiaries, denied applicants, and non-applicants. Our results show that during the early 1990s, the growth in DI can fully explain the employment decline for men only under an extreme assumption about the employment potential of beneficiaries. For the period after the mid-1990s, we find little role for the DI program in explaining the continuing employment decline for men with work limitations. PMID:27158580

DNA-PK Promotes the Mitochondrial, Metabolic, and Physical Decline that Occurs During Aging.

PubMed

Park, Sung-Jun; Gavrilova, Oksana; Brown, Alexandra L; Soto, Jamie E; Bremner, Shannon; Kim, Jeonghan; Xu, Xihui; Yang, Shutong; Um, Jee-Hyun; Koch, Lauren G; Britton, Steven L; Lieber, Richard L; Philp, Andrew; Baar, Keith; Kohama, Steven G; Abel, E Dale; Kim, Myung K; Chung, Jay H

2017-05-02

Hallmarks of aging that negatively impact health include weight gain and reduced physical fitness, which can increase insulin resistance and risk for many diseases, including type 2 diabetes. The underlying mechanism(s) for these phenomena is poorly understood. Here we report that aging increases DNA breaks and activates DNA-dependent protein kinase (DNA-PK) in skeletal muscle, which suppresses mitochondrial function, energy metabolism, and physical fitness. DNA-PK phosphorylates threonines 5 and 7 of HSP90α, decreasing its chaperone function for clients such as AMP-activated protein kinase (AMPK), which is critical for mitochondrial biogenesis and energy metabolism. Decreasing DNA-PK activity increases AMPK activity and prevents weight gain, decline of mitochondrial function, and decline of physical fitness in middle-aged mice and protects against type 2 diabetes. In conclusion, DNA-PK is one of the drivers of the metabolic and fitness decline during aging, and therefore DNA-PK inhibitors may have therapeutic potential in obesity and low exercise capacity. Published by Elsevier Inc.

Does Sensory Function Decline Independently or Concomitantly with Age? Data from the Baltimore Longitudinal Study of Aging.

PubMed

Gadkaree, Shekhar K; Sun, Daniel Q; Li, Carol; Lin, Frank R; Ferrucci, Luigi; Simonsick, Eleanor M; Agrawal, Yuri

2016-01-01

Objectives . To investigate whether sensory function declines independently or in parallel with age within a single individual. Methods . Cross-sectional analysis of Baltimore Longitudinal Study of Aging (BLSA) participants who underwent vision (visual acuity threshold), proprioception (ankle joint proprioceptive threshold), vestibular function (cervical vestibular-evoked myogenic potential), hearing (pure-tone average audiometric threshold), and Health ABC physical performance battery testing. Results . A total of 276 participants (mean age 70 years, range 26-93) underwent all four sensory tests. The function of all four systems declined with age. After age adjustment, there were no significant associations between sensory systems. Among 70-79-year-olds, dual or triple sensory impairment was associated with poorer physical performance. Discussion . Our findings suggest that beyond the common mechanism of aging, other distinct (nonshared) etiologic mechanisms may contribute to decline in each sensory system. Multiple sensory impairments influence physical performance among individuals in middle old-age (age 70-79).

Does Sensory Function Decline Independently or Concomitantly with Age? Data from the Baltimore Longitudinal Study of Aging

PubMed Central

Gadkaree, Shekhar K.; Sun, Daniel Q.; Li, Carol; Lin, Frank R.; Ferrucci, Luigi; Simonsick, Eleanor M.

2016-01-01

Objectives. To investigate whether sensory function declines independently or in parallel with age within a single individual. Methods. Cross-sectional analysis of Baltimore Longitudinal Study of Aging (BLSA) participants who underwent vision (visual acuity threshold), proprioception (ankle joint proprioceptive threshold), vestibular function (cervical vestibular-evoked myogenic potential), hearing (pure-tone average audiometric threshold), and Health ABC physical performance battery testing. Results. A total of 276 participants (mean age 70 years, range 26–93) underwent all four sensory tests. The function of all four systems declined with age. After age adjustment, there were no significant associations between sensory systems. Among 70–79-year-olds, dual or triple sensory impairment was associated with poorer physical performance. Discussion. Our findings suggest that beyond the common mechanism of aging, other distinct (nonshared) etiologic mechanisms may contribute to decline in each sensory system. Multiple sensory impairments influence physical performance among individuals in middle old-age (age 70–79). PMID:27774319

Infectious diseases subspecialty: declining demand challenges and opportunities.

PubMed

Chandrasekar, Pranatharthi; Havlichek, Daniel; Johnson, Leonard B

2014-12-01

Recent match results from the National Resident Matching Program for the subspecialty of infectious diseases show an ongoing decline in the number of fellowship positions filled, and, more important, in the number of applicants, particularly from the pool of international medical graduates. The main reasons for this declining application rate are unclear; in the absence of hard data, we present our viewpoint on this issue. Difficulties in securing visas for permanent residency in the United States, perception of a limited job market, and the explosive growth in the number of hospitalist positions may be important contributing factors. Infectious Diseases Society of America members need to focus on medical students and medical residents in their formative years. We present potential solutions to this problem of declining interest in the field of infectious diseases. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Dietary supplementation with a combination of alpha-lipoic acid, acetyl-L-carnitine, glycerophosphocoline, docosahexaenoic acid, and phosphatidylserine reduces oxidative damage to murine brain and improves cognitive performance.

PubMed

Suchy, James; Chan, Amy; Shea, Thomas B

2009-01-01

Alzheimer disease has a complex etiology composed of nutritional and genetic risk factors and predispositions. Moreover, genetic risk factors for cognitive decline may remain latent pending age-related decline in nutrition, suggesting the potential importance of early nutritional intervention, including preventative approaches. We hypothesized that a combination of multiple nutritional additives may be able to provide neuroprotection. We demonstrate herein that dietary supplementation with a mixture of ALA, ALCAR, GPC, DHA, and PS reduced reactive oxygen species in normal mice by 57% and prevented the increase in reactive oxygen species normally observed in mice lacking murine ApoE when maintained on a vitamin-free, iron-enriched, oxidative-challenge diet. We further demonstrate that supplementation with these agents prevented the marked cognitive decline otherwise observed in normal mice maintained on this challenge diet. These findings add to the growing body of research indicating that key dietary supplementation may delay the progression of age-related cognitive decline.

A Sixteen-year Decline in Dissolved Oxygen in the Central California Current.

PubMed

Ren, Alice S; Chai, Fei; Xue, Huijie; Anderson, David M; Chavez, Francisco P

2018-05-08

A potential consequence of climate change is global decrease in dissolved oxygen at depth in the oceans due to changes in the balance of ventilation, mixing, respiration, and photosynthesis. We present hydrographic cruise observations of declining dissolved oxygen collected along CalCOFI Line 66.7 (Line 67) off of Monterey Bay, in the Central California Current region, and investigate likely mechanisms. Between 1998 and 2013, dissolved oxygen decreased at the mean rate of 1.92 µmol kg -1 year -1 on σ θ 26.6-26.8 kg m -3 isopycnals (250-400 m), translating to a 40% decline from initial concentrations. Two cores of elevated dissolved oxygen decline at 130 and 240 km from shore, which we suggest are a California Undercurrent and a California Current signal respectively, occurred on σ θ ranges of 26.0-26.8 kg m -3 (100-400 m). A box model suggests that small annual changes in dissolved oxygen in source regions are sufficient to be the primary driver of the mid-depth declines. Variation in dissolved oxygen at the bottom of the surface mixed layer suggests that there is also a signal of increased local remineralization.

Regional resource depletion and industry activity: The case of oil and gas in the Gulf of Mexico

USGS Publications Warehouse

Attanasi, E.D.

1986-01-01

Stable and declining oil and gas prices have changed the industry's price expectations and, along with depletion of promising exploration prospects, has resulted in reduced exploration. Even with intensive additional exploration, production in most U.S. areas is expected to decline. What does this imply for the drilling and petroleum industry suppliers in particular regions? How should planners in government and the private sector project and incorporate the consequences of these changes in their strategies? This paper answers these questions for the industry operating in the offshore Gulf of Mexico. Future oil and gas production, as well as demand for offshore drilling and production facilities, are shown to depend on the size distribution of undiscovered fields, their associated production costs, and oil and gas prices. Declining well productivity is a consequence of development of progressively smaller fields so that long-run drilling demand should not decline in proportion to the expected production decline. Calculations show a substantial payoff to the drilling industry, in terms of potential demand increases, if it can develop and implement cost reducing technologies. Implications of these results for other offshore producing areas such as the North Sea are also discussed. ?? 1986.

Nanostructural control of methane release in kerogen and its implications to wellbore production decline

NASA Astrophysics Data System (ADS)

Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

2016-06-01

Despite massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix-a limiting step in shale gas extraction. Using molecular simulations, we here show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30-47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3-35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.

Projected response of an endangered marine turtle population to climate change

NASA Astrophysics Data System (ADS)

Saba, Vincent S.; Stock, Charles A.; Spotila, James R.; Paladino, Frank V.; Tomillo, Pilar Santidrián

2012-11-01

Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Critically endangered leatherback turtles in the eastern Pacific Ocean are excellent candidates for such an assessment because their sensitivity to contemporary climate variability has been substantially studied. If incidental fisheries mortality is eliminated, this population still faces the challenge of recovery in a rapidly changing climate. Here we combined an Earth system model, climate model projections assessed by the Intergovernmental Panel on Climate Change and a population dynamics model to estimate a 7% per decade decline in the Costa Rica nesting population over the twenty-first century. Whereas changes in ocean conditions had a small effect on the population, the ~2.5°C warming of the nesting beach was the primary driver of the decline through reduced hatching success and hatchling emergence rate. Hatchling sex ratio did not substantially change. Adjusting nesting phenology or changing nesting sites may not entirely prevent the decline, but could offset the decline rate. However, if future observations show a long-term decline in hatching success and emergence rate, anthropogenic climate mitigation of nests (for example, shading, irrigation) may be able to preserve the nesting population.

Carotid disease at age 73 and cognitive change from age 70 to 76 years: A longitudinal cohort study

PubMed Central

Allerhand, Michael; Eadie, Elizabeth; Thomas, Avril; Corley, Janey; Pattie, Alison; Taylor, Adele; Shenkin, Susan D; Cox, Simon; Gow, Alan; Starr, John M; Deary, Ian J

2016-01-01

Cognitive decline and carotid artery atheroma are common at older ages. In community-dwelling subjects, we assessed cognition at ages 70, 73 and 76 and carotid Doppler ultrasound at age 73, to determine whether carotid stenosis was related to cognitive decline. We used latent growth curve models to examine associations between four carotid measures (internal carotid artery stenosis, velocity, pulsatility and resistivity indices) and four cognitive ability domains (memory, visuospatial function, crystallised intelligence, processing speed) adjusted for cognitive ability at age 11, current age, gender and vascular risk factors. Amongst 866 participants, carotid stenosis (median 12.96%) was not associated with cognitive abilities at age 70 or cognitive decline from age 70 to 76. Increased ICA pulsatility and resistivity indices were associated with slower processing speed (both P < 0.001) and worse visuospatial function (P = 0.036, 0.031, respectively) at age 70, and declining crystallised intelligence from ages 70 to 76 (P = 0.008, 0.006, respectively). The findings suggest that vascular stiffening, rather than carotid luminal narrowing, adversely influences cognitive ageing and provides a potential target for ameliorating age-related cognitive decline. PMID:28155579

Carotid disease at age 73 and cognitive change from age 70 to 76 years: A longitudinal cohort study.

PubMed

Wardlaw, Joanna M; Allerhand, Michael; Eadie, Elizabeth; Thomas, Avril; Corley, Janey; Pattie, Alison; Taylor, Adele; Shenkin, Susan D; Cox, Simon; Gow, Alan; Starr, John M; Deary, Ian J

2017-08-01

Cognitive decline and carotid artery atheroma are common at older ages. In community-dwelling subjects, we assessed cognition at ages 70, 73 and 76 and carotid Doppler ultrasound at age 73, to determine whether carotid stenosis was related to cognitive decline. We used latent growth curve models to examine associations between four carotid measures (internal carotid artery stenosis, velocity, pulsatility and resistivity indices) and four cognitive ability domains (memory, visuospatial function, crystallised intelligence, processing speed) adjusted for cognitive ability at age 11, current age, gender and vascular risk factors. Amongst 866 participants, carotid stenosis (median 12.96%) was not associated with cognitive abilities at age 70 or cognitive decline from age 70 to 76. Increased ICA pulsatility and resistivity indices were associated with slower processing speed (both P < 0.001) and worse visuospatial function ( P = 0.036, 0.031, respectively) at age 70, and declining crystallised intelligence from ages 70 to 76 ( P = 0.008, 0.006, respectively). The findings suggest that vascular stiffening, rather than carotid luminal narrowing, adversely influences cognitive ageing and provides a potential target for ameliorating age-related cognitive decline.

Age-related differences in associative memory: Empirical evidence and theoretical perspectives.

PubMed

Naveh-Benjamin, Moshe; Mayr, Ulrich

2018-02-01

Systematic research and anecdotal evidence both indicate declines in episodic memory in older adults in good health without dementia-related disorders. Several hypotheses have been proposed to explain these age-related changes in episodic memory, some of which attribute such declines to a deterioration in associative memory. The current special issue of Psychology and Aging on Age-Related Differences in Associative Memory includes 16 articles by top researchers in the area of memory and aging. Their contributions provide a wealth of empirical work that addresses different aspects of aging and associative memory, including different mediators and predictors of age-related declines in binding and associative memory, cognitive, noncognitive, genetic, and neuro-related ones. The contributions also address the processing phases where these declines manifest themselves and look at ways to ameliorate these age-related declines. Furthermore, the contributions in this issue draw on different theoretical perspectives to explain age-related changes in associative memory and provide a wealth of varying methodologies to assess older and younger adults' performance. Finally, although most of the studies focus on normative/healthy aging, some of them contain insights that are potentially applicable to disorders and pathologies. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Physical function and independence 1 year after myocardial infarction: observations from the Translational Research Investigating Underlying disparities in recovery from acute Myocardial infarction: Patients' Health status registry.

PubMed

Dodson, John A; Arnold, Suzanne V; Reid, Kimberly J; Gill, Thomas M; Rich, Michael W; Masoudi, Frederick A; Spertus, John A; Krumholz, Harlan M; Alexander, Karen P

2012-05-01

Acute myocardial infarction (AMI) may contribute to health status declines including "independence loss" and "physical function decline." Despite the importance of these outcomes for prognosis and quality of life, their incidence and predictors have not been well described. We studied 2,002 patients with AMI enrolled across 24 sites in the TRIUMPH registry who completed assessments of independence and physical function at the time of AMI and 1 year later. Independence was evaluated by the EuroQol-5D (mobility, self-care, and usual activities), and physical function was assessed with the Short Form-12 physical component score. Declines in ≥1 level on EuroQol-5D and >5 points in PCS were considered clinically significant changes. Hierarchical, multivariable, modified Poisson regression models accounting for within-site variability were used to identify predictors of independence loss and physical function decline. One-year post AMI, 43.0% of patients experienced health status declines: 12.8% independence loss alone, 15.2% physical function decline alone, and 15.0% both. After adjustment, variables that predicted independence loss included female sex, nonwhite race, unmarried status, uninsured status, end-stage renal disease, and depression. Variables that predicted physical function decline were uninsured status, lack of cardiac rehabilitation referral, and absence of pre-AMI angina. Age was not predictive of either outcome after adjustment. >40% of patients experience independence loss or physical function decline 1 year after AMI. These changes are distinct but can occur simultaneously. Although some risk factors are not modifiable, others suggest potential targets for strategies to preserve patients' health status. Copyright © 2012 Mosby, Inc. All rights reserved.

Decline in cognitive function and risk of elder self-neglect: finding from the Chicago Health Aging Project.

PubMed

Dong, XinQi; Simon, Melissa A; Wilson, Robert S; Mendes de Leon, Carlos F; Rajan, K Bharat; Evans, Denis A

2010-12-01

To examine the longitudinal association between decline in cognitive function and risk of elder self-neglect in a community-dwelling population. Prospective population-based study. Geographically defined community in Chicago. Community-dwelling subjects reported to the social services agency from 1993 to 2005 for self-neglect who also participated in the Chicago Health Aging Project (CHAP). Of the 5,519 participants in CHAP, 1,017 were reported to social services agency for suspected elder self-neglect from 1993 to 2005. Social services agency identified reported elder self-neglect. The primary predictor was decline in cognitive function assessed using the Mini-Mental State Examination (MMSE), the Symbol Digit Modalities Test (Executive Function), and immediate and delayed recall of the East Boston Memory Test (Episodic Memory). An index of global cognitive function scores was derived by averaging z-scores of all tests. Outcome of interest was elder self-neglect. Logistic and linear regression models were used to assess these longitudinal associations. After adjusting for potential confounding factors, decline in global cognitive function, MMSE score, and episodic memory were not independently associated with greater risk of reported and confirmed elder self-neglect. Decline in executive function was associated with greater risk of reported and confirmed elder self-neglect. Decline in global cognitive function was associated with greater risk of greater self-neglect severity (parameter estimate=0.76, standard error=0.31, P=.01). Decline in executive function was associated with risk of reported and confirmed elder self-neglect. Decline in global cognitive function was associated with risk of greater self-neglect severity. © 2010, Copyright the Authors. Journal compilation © 2010, The American Geriatrics Society.

Risk factors for lung function decline in a large cohort of young cystic fibrosis patients.

PubMed

Cogen, Jonathan; Emerson, Julia; Sanders, Don B; Ren, Clement; Schechter, Michael S; Gibson, Ronald L; Morgan, Wayne; Rosenfeld, Margaret

2015-08-01

To identify novel risk factors and corroborate previously identified risk factors for mean annual decline in FEV1% predicted in a large, contemporary, United States cohort of young cystic fibrosis (CF) patients. Retrospective observational study of participants in the EPIC Observational Study, who were Pseudomonas-negative and ≤12 years of age at enrollment in 2004-2006. The associations between potential demographic, clinical, and environmental risk factors evaluated during the baseline year and subsequent mean annual decline in FEV1 percent predicted were evaluated using generalized estimating equations. The 946 participants in the current analysis were followed for a mean of 6.2 (SD 1.3) years. Mean annual decline in FEV1% predicted was 1.01% (95%CI 0.85-1.17%). Children with one or no F508del mutations had a significantly smaller annual decline in FEV1 compared to F508del homozygotes. In a multivariable model, risk factors during the baseline year associated with a larger subsequent mean annual lung function decline included female gender, frequent or productive cough, low BMI (<66th percentile, median in the cohort), ≥1 pulmonary exacerbation, high FEV1 (≥115% predicted, in the top quartile), and respiratory culture positive for methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, or Stenotrophomonas maltophilia. We have identified a range of risk factors for FEV1 decline in a large cohort of young, CF patients who were Pa negative at enrollment, including novel as well as previously identified characteristics. These results could inform the design of a clinical trial in which rate of FEV1 decline is the primary endpoint and identify high-risk groups that may benefit from closer monitoring. © 2015 Wiley Periodicals, Inc.

Increasing Body Mass Index Predicts Rapid Decline in Renal Function: A 5 Year Retrospective Study.

PubMed

Ma, Xiaojing; Zhang, Chengyin; Su, Hong; Gong, Xiaojie; Kong, Xianglei

2018-05-02

While obesity is a recognized risk factor for chronic kidney disease, it remains unclear whether change in body mass index (ΔBMI ) is independently associated with decline in renal function (evaluated by the change in estimated glomerular filtration rate, ΔeGFR) over time. Accordingly, to help clarify this we conducted a retrospective study to measure the association of ΔBMI with decline in renal function in Chinese adult population. A total of 4007 adults (aged 45.3±13.7 years, 68.6% male) without chronic kidney disease at baseline were enrolled between 2008 and 2013. Logistic regression models were applied to explore the relationships between baseline BMI and ΔBMI, and rapid decline in renal function (defined as the lowest quartile of ΔeGFR ). During 5 years of follow-up, the ΔBMI and ΔeGFR were 0.47±1.6 (kg/m 2 ) and -3.0±8.8 (ml/min/1.73 m 2 ), respectively. After adjusted for potential confounders, ΔBMI (per 1 kg/m 2 increase) was independently associated with the rapid decline in renal function [with a fully adjusted OR of 1.12 (95% CI, 1.05 to 1.20). By contrast, the baseline BMI was not associated with rapid decline in renal function [OR=1.05 (95% CI, 0.98 to 1.13)]. The results were robust among 2948 hypertension-free and diabetes-free participants, the adjusted ORs of ΔBMI and baseline BMI were 1.14 (95% CI, 1.05 to 1.23) and 1.0 (95% CI, 0.96 to 1.04) for rapid decline in renal function, respectively. The study revealed that increasing ΔBMI predicts rapid decline in renal function. © Georg Thieme Verlag KG Stuttgart · New York.

Supplementing cognitive aging: a selective review of the effects of ginkgo biloba and a number of everyday nutritional substances.

PubMed

Brown, Louise A; Riby, Leigh M; Reay, Jonathon L

2010-01-01

This review concerns a number of substances that have been receiving much attention, particularly in the media, for their potential to protect against age-related cognitive decline, and a focus is placed upon recent findings. Omega-3 fatty acids appear to play important roles in preserving neuronal structure and function and minimizing cognitive decline, whereas the antioxidant vitamins C and E appear to be particularly beneficial for combating age-related oxidative stress when administered in combination. Fruit and vegetable polyphenols also offer great potential, although most research thus far has involved rodents. Finally, there is mixed evidence regarding the cognitive enhancing properties of Ginkgo biloba, and the B vitamins folate and cobalamin, with all of these requiring further investigation.

Synapse Specificity of Long-Term Potentiation Breaks Down with Aging

ERIC Educational Resources Information Center

Ris, Laurence; Godaux, Emile

2007-01-01

Memory shows age-related decline. According to the current prevailing theoretical model, encoding of memories relies on modifications in the strength of the synapses connecting the different cells within a neuronal network. The selective increases in synaptic weight are thought to be biologically implemented by long-term potentiation (LTP). Here,…

A Steady State Visually Evoked Potential Investigation of Memory and Ageing

ERIC Educational Resources Information Center

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-01-01

Old age is generally accompanied by a decline in memory performance. Specifically, neuroimaging and electrophysiological studies have revealed that there are age-related changes in the neural correlates of episodic and working memory. This study investigated age-associated changes in the steady state visually evoked potential (SSVEP) amplitude and…

Modeling potential river management conflicts between frogs and salmonids

Treesearch

Steven F. Railsback; Bret C. Harvey; Sarah J. Kupferberg; Margaret M. Lang; Scott McBain; Hart H. Welsh

2016-01-01

Management of regulated rivers for yellow-legged frogs (Rana boylii) and salmonids exemplifies potential conflicts among species adapted to different parts of the natural flow and temperature regimes. Yellow-legged frogs oviposit in rivers in spring and depend on declining flows and warming temperatures for egg and tadpole survival and growth,...

Anxiety symptoms and risk of cognitive decline in older community-dwelling men.

PubMed

Kassem, Ahmed M; Ganguli, Mary; Yaffe, Kristine; Hanlon, Joseph T; Lopez, Oscar L; Wilson, John W; Cauley, Jane A

2017-07-01

Previous research regarding anxiety as a predictor of future cognitive decline in older adults is limited and inconsistent. We examined the independent relationship between anxiety symptoms and subsequent cognitive decline. We included 2,818 community-dwelling older men (mean age = 76.1, SD ±5.3 years) who were followed on an average for 3.4 years. We assessed anxiety symptoms at baseline using the Goldberg Anxiety Scale (GAS; range = 0-9). We assessed cognitive function at baseline and at two subsequent visits using the Modified Mini-Mental State Examination (3MS; global cognition) and the Trails B test (executive function). At baseline, there were 690 (24%) men with mild anxiety symptoms (GAS 1-4) and 226 (8%) men with moderate/severe symptoms (GAS 5-9). Men with anxiety symptoms were more likely to have depressed mood, poor sleep, more chronic medical conditions, and more impairment in activities of daily living compared to those with no anxiety symptoms. Compared to those with no anxiety symptoms at baseline, men with any anxiety symptoms were more likely to have substantial worsening in Trails B completion time (OR = 1.56, 95% CI 1.19, 2.05). The association was attenuated after adjusting for potential confounders, including depression and poor sleep, but remained significant (OR = 1.40, 95% CI 1.04, 1.88). In cognitively healthy older men, mild anxiety symptoms may potentially predict future decline in executive functioning. Anxiety is likely a manifestation of an underlying neurodegenerative process rather than a cause.

Ozone Sensitivity in Sweet Corn (Zea mays L.) Plants: A Possible Relationship to Water Balance

PubMed Central

Harris, Michael J.; Heath, Robert L.

1981-01-01

Stomatal characteristics affecting gas exchange were compared in two sweet corn hybrids (var. Bonanza and Monarch Advance) which differ in foliar ozone sensitivity. No significant differences were observed in stomatal frequencies, guard cell lengths, or conductances to water vapor diffusion. When plant water status was compared, leaf-water potentials for the ozone-resistant cultivar, Bonanza, were lower. A comparison of the relationship between soil- and leaf-water potential indicated that the leaf-water potential of Bonanza was more sensitive to declines in soil-water potential. Additionally, a comparison of stomatal conductance to water vapor diffusion as soil moisture declined and following root detachment indicated that stomata of Bonanza were, likewise, more sensitive to increasing water stress. Data suggest that these differences are attributable to a greater shoot-to-root fresh weight ratio and higher resistance to water movement in the water-conducting tissues for Bonanza. Our observations suggest that root and water delivery system characteristics play a major contributory role in the determination of foliar ozone sensitivity in this species. PMID:16662019

Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications

NASA Astrophysics Data System (ADS)

DeWeaver, Eric T.; Bitz, Cecilia M.; Tremblay, L.-Bruno

This volume addresses the rapid decline of Arctic sea ice, placing recent sea ice decline in the context of past observations, climate model simulations and projections, and simple models of the climate sensitivity of sea ice. Highlights of the work presented here include • An appraisal of the role played by wind forcing in driving the decline; • A reconstruction of Arctic sea ice conditions prior to human observations, based on proxy data from sediments; • A modeling approach for assessing the impact of sea ice decline on polar bears, used as input to the U.S. Fish and Wildlife Service's decision to list the polar bear as a threatened species under the Endangered Species Act; • Contrasting studies on the existence of a "tipping point," beyond which Arctic sea ice decline will become (or has already become) irreversible, including an examination of the role of the small ice cap instability in global warming simulations; • A significant summertime atmospheric response to sea ice reduction in an atmospheric general circulation model, suggesting a positive feedback and the potential for short-term climate prediction. The book will be of interest to researchers attempting to understand the recent behavior of Arctic sea ice, model projections of future sea ice loss, and the consequences of sea ice loss for the natural and human systems of the Arctic.

Potential causes for amphibian declines in Puerto Rico

USGS Publications Warehouse

Burrowes, P.A.; Joglar, R.L.; Green, David E.

2004-01-01

We monitored 11 populations of eight species of Eleutherodactylus in Puerto Rico from 1989 through 2001. We determined relative abundance of active frogs along transects established in the Caribbean National Forest (El Yunque), Carite Forest, San Lorenzo, and in the vicinity of San Juan. Three species (Eleutherodactylus karlschmidti, E. jasperi, and E. eneidae) are presumed to be extinct and eight populations of six different species of endemic Eleutherodactylus are significantly declining at elevations above 400 m. Of the many suspected causes of amphibian declines around the world, we focused on climate change and disease. Temperature and precipitation data from 1970a??2000 were analyzed to determine the general pattern of oscillations and deviations that could be correlated with amphibian declines. We examined a total of 106 tissues taken from museum specimens collected from 1961a??1978 and from live frogs in 2000. We found chytrid fungi in two species collected at El Yunque as early as 1976, this is the first report of chytrid fungus in the Caribbean. Analysis of weather data indicates a significant warming trend and an association between years with extended periods of drought and the decline of amphibians in Puerto Rico. The 1970's and 1990's, which represent the periods of amphibian extirpations and declines, were significantly drier than average. We suggest a possible synergistic interaction between drought and the pathological effect of the chytrid fungus on amphibian populations.

The decline of teacher autonomy: Tears or cheers?

NASA Astrophysics Data System (ADS)

Anderson, Lorin W.

1987-09-01

In the United States teacher autonomy has been declining for at least a decade. This decline can be attributed in large part to three factors. First, uniform staff development programmes based on research on effective teaching have become widespread. Second, classroom observations have become an integral part of imposed teacher evaluations. Third, school principals have been called on to assume the role of `instructional leader'. While some may perceive the decline of teacher autonomy negatively, at least two benefits of this decline have been identified. First, a `common language' by which teachers can discuss the problems and potential of instruction and teaching among themselves and with school administrators is developing. Second, the likelihood that teachers will achieve a truly professional status is enhanced. Many educators write as if the natural result of a decline in teacher autonomy is standardization; that is, the cloning of teachers. This article negates such pessimism. Teacher autonomy, like many educational variables, exists along a continuum. As a consequence, a midpoint on the autonomy continuum — a balance between uniqueness and standardization, between license and responsibility — is the desirable state of affairs. Finally, autonomy should be earned by teachers, not simply given to them. In this regard, greater concern should be given to teachers' preparation for, and induction into, their roles as school teachers. Similarly, increases in autonomy should mirror increases in teacher status; status defined in terms of teacher experience, expertise, and excellence.

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance.

PubMed

Roddy, Adam B; Simonin, Kevin A; McCulloh, Katherine A; Brodersen, Craig R; Dawson, Todd E

2018-03-30

For most angiosperms, producing and maintaining flowers is critical to sexual reproduction, yet little is known about the physiological processes involved in maintaining flowers throughout anthesis. Among extant species, flowers of the genus Calycanthus have the highest hydraulic conductance and vein densities of species measured to date, yet they can wilt by late morning under hot conditions. Here, we combine diurnal measurements of gas exchange and water potential, pressure-volume relations, functional responses of gas exchange, and characterization of embolism formation using high resolution X-ray computed microtomography to determine drought responses of Calycanthus flowers. Transpiration from flowers frequently exceeded transpiration from leaves, and flowers were unable to limit transpiration under conditions of high vapour pressure deficit. As a result, they rely heavily on hydraulic capacitance to prevent water potential declines. Despite having high water potentials at turgor loss, flowers were very resistant to embolism formation, with no embolism apparent until tepal water potentials had declined to -2 MPa. Although Calycanthus flowers remain connected to the stem xylem and have high hydraulic capacitance, their inability to curtail transpiration leads to turgor loss. These results suggest that extreme climate events may cause flower failure, potentially preventing successful reproduction. © 2018 John Wiley & Sons Ltd.

Multiple prethymic defects underlie age-related loss of T progenitor competence

PubMed Central

Zediak, Valerie P.; Maillard, Ivan

2007-01-01

Aging in mice and humans is characterized by declining T-lymphocyte production in the thymus, yet it is unclear whether aging impacts the T-lineage potential of hematopoietic progenitors. Although alterations in the lymphoid progenitor content of aged mouse bone marrow (BM) have been described, irradiation-reconstitution experiments have failed to reveal defects in T-lineage potential of BM hematopoietic progenitors or purified hematopoietic stem cells (HSCs) from aged mice. Here, we assessed T-progenitor potential in unmanipulated recipient mice without conditioning irradiation. T-progenitor potential was reduced in aged BM compared with young BM, and this reduction was apparent at the earliest stages of intrathymic differentiation. Further, enriched populations of aged HSCs or multipotent progenitors (MPPs) gave rise to fewer T-lineage cells than their young counterparts. Whereas the T-precursor frequency within the MPP pool was unchanged, there was a 4-fold decline in T-precursor frequency within the HSC pool. In addition, among the T-competent HSC clones, there were fewer highly proliferative clones in the aged HSC pool than in the young HSC pool. These results identify T-compromised aged HSCs and define the nature and cellular sites of prethymic, age-related defects in T-lineage differentiation potential. PMID:17456721

Creutzfeldt-Jakob Disease

MedlinePlus

... damage leads to rapid decline in thinking and reasoning as well as involuntary muscle movements, confusion, difficulty ... been tested but have not shown any benefit. Clinical studies of potential CJD treatments are complicated by ...

Rationale and design of the CAROLINA® - cognition substudy: a randomised controlled trial on cognitive outcomes of linagliptin versus glimepiride in patients with type 2 diabetes mellitus.

PubMed

Biessels, Geert Jan; Janssen, Jolien; van den Berg, Esther; Zinman, Bernard; Espeland, Mark A; Mattheus, Michaela; Johansen, Odd Erik

2018-01-15

Type 2 diabetes mellitus is associated with cognitive dysfunction and an increased risk of dementia. Linagliptin is a glucose-lowering agent of the dipeptidyl peptidase-IV (DPP-IV) inhibitor class that is of particular interest for the prevention of accelerated cognitive decline, because it may potentially benefit the brain through pleiotropic effects, beyond glucose lowering. This paper presents the design of a study that aims to establish if linagliptin is superior to the sulfonylurea glimepiride in the prevention of accelerated cognitive decline in patients with type 2 diabetes mellitus. The cognition substudy is an integral part of the ongoing event-driven, randomised, double blind CARdiOvascular safety of LINAgliptin (CAROLINA®) trial, which evaluates the effect of treatment with linagliptin versus glimepiride on cardiovascular outcomes. CAROLINA® includes patients with type 2 diabetes mellitus with sub-optimal glycaemic control at elevated cardiovascular risk. The substudy will evaluate patients randomised and treated who have a baseline Mini Mental State Examination (MMSE) score ≥ 24, documented years of formal education with at least one valid cognitive assessment at baseline and during follow-up. The primary cognitive outcome is the occurrence of accelerated cognitive decline at the end of follow-up. The two treatment groups will be compared by using a logistic regression. Accelerated cognitive decline is defined as a rate of cognitive decline that falls at or below the 16th percentile of decline for the whole cohort on either the MMSE or a combined score of the trail making and verbal fluency test. Potential confounders are taken into account at an individual patient level, using a regression based index. Between December 2010 and December 2012, 6042 patients were randomised and treated with either linagliptin (5 mg) or glimepiride (1-4 mg) once daily in CAROLINA®. Cognitive tests were conducted in nearly 4500 participants at baseline and are scheduled for two subsequent assessments, after 160 weeks of follow-up and end of follow-up. This substudy of the ongoing CAROLINA® trial will establish if linagliptin is superior to glimepiride in the prevention of accelerated cognitive decline in patients with type 2 diabetes mellitus. Final results are expected in 2019. ClinicalTrials.gov Identifier: NCT 01243424 .

From cooperation to combat: adverse effect of thermal stress in a symbiotic coral-crustacean community.

PubMed

Stella, J S; Munday, P L; Walker, S P W; Pratchett, M S; Jones, G P

2014-04-01

Although mutualisms are ubiquitous in nature, our understanding of the potential impacts of climate change on these important ecological interactions is deficient. Here, we report on a thermal stress-related shift from cooperation to antagonism between members of a mutualistic coral-dwelling community. Increased mortality of coral-defending crustacean symbionts Trapezia cymodoce (coral crab) and Alpheus lottini (snapping shrimp) was observed in response to experimentally elevated temperatures and reduced coral-host (Pocillopora damicornis) condition. However, strong differential numerical effects occurred among crustaceans as a function of species and sex, with shrimp (75%), and female crabs (55%), exhibiting the fastest and greatest declines in numbers. These declines were due to forceful eviction from the coral-host by male crabs. Furthermore, surviving female crabs were impacted by a dramatic decline (85%) in egg production, which could have deleterious consequences for population sustainability. Our results suggest that elevated temperature switches the fundamental nature of this interaction from cooperation to competition, leading to asymmetrical effects on species and/or sexes. Our study illustrates the importance of evaluating not only individual responses to climate change, but also potentially fragile interactions within and among susceptible species.

Ecological intensification to mitigate impacts of conventional intensive land use on pollinators and pollination.

PubMed

Kovács-Hostyánszki, Anikó; Espíndola, Anahí; Vanbergen, Adam J; Settele, Josef; Kremen, Claire; Dicks, Lynn V

2017-05-01

Worldwide, human appropriation of ecosystems is disrupting plant-pollinator communities and pollination function through habitat conversion and landscape homogenisation. Conversion to agriculture is destroying and degrading semi-natural ecosystems while conventional land-use intensification (e.g. industrial management of large-scale monocultures with high chemical inputs) homogenises landscape structure and quality. Together, these anthropogenic processes reduce the connectivity of populations and erode floral and nesting resources to undermine pollinator abundance and diversity, and ultimately pollination services. Ecological intensification of agriculture represents a strategic alternative to ameliorate these drivers of pollinator decline while supporting sustainable food production, by promoting biodiversity beneficial to agricultural production through management practices such as intercropping, crop rotations, farm-level diversification and reduced agrochemical use. We critically evaluate its potential to address and reverse the land use and management trends currently degrading pollinator communities and potentially causing widespread pollination deficits. We find that many of the practices that constitute ecological intensification can contribute to mitigating the drivers of pollinator decline. Our findings support ecological intensification as a solution to pollinator declines, and we discuss ways to promote it in agricultural policy and practice. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Ten-year change in plasma amyloid beta levels and late-life cognitive decline.

PubMed

Okereke, Olivia I; Xia, Weiming; Selkoe, Dennis J; Grodstein, Francine

2009-10-01

Plasma levels of amyloid beta peptide (Abeta) are potential biomarkers of early cognitive impairment and decline and of Alzheimer disease risk. To relate midlife plasma Abeta measures and 10-year change in plasma Abeta measures since midlife to late-life cognitive decline. Prospective study of a population-based sample. Academic research. Plasma Abeta40 and Abeta42 levels were measured in 481 Nurses' Health Study participants in late midlife (mean age, 63.6 years) and again 10 years later (mean age, 74.6 years). Cognitive testing also began 10 years after the initial blood draw. Participants completed 3 repeated telephone-based assessments (mean span, 4.1 years). Multivariable linear mixed-effects models were used to estimate relations of midlife plasma Abeta40 to Abeta42 ratios and Abeta42 levels to late-life cognitive decline, as well as relations of 10-year change in Abeta40 to Abeta42 ratios and Abeta42 levels to cognitive decline. The 3 primary outcomes were the Telephone Interview for Cognitive Status (TICS) findings, a global score averaging the results of all tests (TICS, immediate and delayed verbal recall, category fluency, and attention), and a verbal memory score averaging the results of 4 tests of verbal recall. Higher midlife plasma Abeta40 to Abeta42 ratios were associated with worse late-life decline on the global score (P = .04 for trend). Furthermore, increase in Abeta40 to Abeta42 ratios since midlife predicted greater decline in the global score (P = .03 for trend) and in the TICS (P = .02 for trend). There was no association of cognitive decline with midlife plasma Abeta42 levels alone or with change in Abeta42 levels since midlife. In this large community-dwelling sample, higher plasma Abeta40 to Abeta42 ratios in late midlife and increases in Abeta40 to Abeta42 ratios 10 years later were significantly associated with greater decline in global cognition at late life.

Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey.

PubMed

Matchar, David B; Chei, Choy-Lye; Yin, Zhao-Xue; Koh, Victoria; Chakraborty, Bibhas; Shi, Xiao-Ming; Zeng, Yi

2016-10-01

Vitamin D has a neuroprotective function, potentially important for the prevention of cognitive decline. Prospective studies from Western countries support an association between lower vitamin D level and future cognitive decline in elderly people. No prospective study has examined this association in Asia. This community-based cohort study of elderly people in China follows 1,202 cognitively intact adults aged ≥60 years for a mean duration of 2 years. Plasma vitamin D level was measured at the baseline. Cognitive state of participants was assessed using the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score <18. Cognitive decline was defined as ≥3 points decline from baseline. Multivariable logistic regression models were used to examine the association between quartiles of vitamin D levels with cognitive decline and incidence of cognitive impairment. Participants with low vitamin D level had an increased risk of cognitive decline. Compared with the highest quartile of vitamin D levels, the multivariable odds ratios (ORs; 95% confidence interval) for cognitive decline were 2.1 (1.3-3.4) for the second highest quartile, 2.2 (1.4-3.6) for the third highest quartile, and 2.0 (1.2-3.3) for the lowest quartile. The multivariable ORs of incident cognitive impairment for the second highest, third highest, and lowest versus highest quartiles of vitamin D levels were 1.9 (0.9-4.1), 2.6 (1.2-5.6), and 3.2 (1.5-6.6), respectively. This first follow-up study of elderly people, including the oldest-old, in Asia shows that low vitamin D levels were associated with increased risk of subsequent cognitive decline and impairment. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Predicting and setting conservation priorities for Bolivian mammals based on biological correlates of the risk of decline.

PubMed

Peñaranda, Diego A; Simonetti, Javier A

2015-06-01

The recognition that growing proportions of species worldwide are endangered has led to the development of comparative analyses to elucidate why some species are more prone to extinction than others. Understanding factors and patterns of species vulnerability might provide an opportunity to develop proactive conservation strategies. Such comparative analyses are of special concern at national scales because this is the scale at which most conservation initiatives take place. We applied powerful ensemble learning models to test for biological correlates of the risk of decline among the Bolivian mammals to understand species vulnerability at a national scale and to predict the population trend for poorly known species. Risk of decline was nonrandomly distributed: higher proportions of large-sized taxa were under decline, whereas small-sized taxa were less vulnerable. Body mass, mode of life (i.e., aquatic, terrestrial, volant), geographic range size, litter size, home range, niche specialization, and reproductive potential were strongly associated with species vulnerability. Moreover, we found interacting and nonlinear effects of key traits on the risk of decline of mammals at a national scale. Our model predicted 35 data-deficient species in decline on the basis of their biological vulnerability, which should receive more attention in order to prevent their decline. Our results highlight the relevance of comparative analysis at relatively narrow geographical scales, reveal previously unknown factors related to species vulnerability, and offer species-by-species outcomes that can be used to identify targets for conservation, especially for insufficiently known species. © 2015 Society for Conservation Biology.

Self-rated health is associated with subsequent functional decline among older adults in Japan.

PubMed

Hirosaki, Mayumi; Okumiya, Kiyohito; Wada, Taizo; Ishine, Masayuki; Sakamoto, Ryota; Ishimoto, Yasuko; Kasahara, Yoriko; Kimura, Yumi; Fukutomi, Eriko; Chen, Wen Ling; Nakatsuka, Masahiro; Fujisawa, Michiko; Otsuka, Kuniaki; Matsubayashi, Kozo

2017-09-01

Previous studies have reported that self-rated health (SRH) predicts subsequent mortality. However, less is known about the association between SRH and functional ability. The aim of this study was to examine whether SRH predicts decline in basic activities of daily living (ADL), even after adjustment for depression, among community-dwelling older adults in Japan. A three-year prospective cohort study was conducted among 654 residents aged 65 years and older without disability in performing basic ADL at baseline. SRH was assessed using a visual analogue scale (range; 0-100), and dichotomized into low and high groups. Information on functional ability, sociodemographic factors, depressive symptoms, and medical conditions were obtained using a self-administered questionnaire. Logistic regression analysis was used to examine the association between baseline SRH and functional decline three years later. One hundred and eight (16.5%) participants reported a decline in basic ADL at the three-year follow-up. Multiple logistic regression analysis showed that the low SRH group had a higher risk for functional decline compared to the high SRH group, even after controlling for potential confounding factors (odds ratio (OR) = 2.4; 95% confidence interval (CI) = 1.3-4.4). Furthermore, a 10-point difference in SRH score was associated with subsequent functional decline (OR = 1.37; 95% CI = 1.16-1.61). SRH was an independent predictor of functional decline. SRH could be a simple assessment tool for predicting the loss or maintenance of functional ability in community-dwelling older adults. Positive self-evaluation might be useful to maintain an active lifestyle and stay healthy.

Advances in development reverse fertility declines.

PubMed

Myrskylä, Mikko; Kohler, Hans-Peter; Billari, Francesco C

2009-08-06

During the twentieth century, the global population has gone through unprecedented increases in economic and social development that coincided with substantial declines in human fertility and population growth rates. The negative association of fertility with economic and social development has therefore become one of the most solidly established and generally accepted empirical regularities in the social sciences. As a result of this close connection between development and fertility decline, more than half of the global population now lives in regions with below-replacement fertility (less than 2.1 children per woman). In many highly developed countries, the trend towards low fertility has also been deemed irreversible. Rapid population ageing, and in some cases the prospect of significant population decline, have therefore become a central socioeconomic concern and policy challenge. Here we show, using new cross-sectional and longitudinal analyses of the total fertility rate and the human development index (HDI), a fundamental change in the well-established negative relationship between fertility and development as the global population entered the twenty-first century. Although development continues to promote fertility decline at low and medium HDI levels, our analyses show that at advanced HDI levels, further development can reverse the declining trend in fertility. The previously negative development-fertility relationship has become J-shaped, with the HDI being positively associated with fertility among highly developed countries. This reversal of fertility decline as a result of continued economic and social development has the potential to slow the rates of population ageing, thereby ameliorating the social and economic problems that have been associated with the emergence and persistence of very low fertility.

Do Customers Flee From HIV? A Survey of HIV Stigma and Its Potential Economic Consequences on Small Businesses in Tshwane (Pretoria), South Africa.

PubMed

Chao, Li-Wei; Szrek, Helena; Leite, Rui; Ramlagan, Shandir; Peltzer, Karl

2017-01-01

HIV stigma and discrimination affect care-seeking behavior and may also affect entrepreneurial activity. We interview 2382 individuals in Pretoria, South Africa, and show that respondents believe that businesses with known HIV+ workers may lose up to half of their customers, although the impact depends on the type of business. Survey respondents' fear of getting HIV from consuming everyday products sold by the business-despite a real infection risk of zero-was a major factor driving perceived decline in customers, especially among food businesses. Respondents' perceptions of the decline in overall life satisfaction when one gets sick from HIV and the respondent's dislike of people with HIV were also important predictors of potential customer exit. We suggest policy mechanisms that could improve the earnings potential of HIV+ workers: reducing public health scare tactics that exacerbate irrational fear of HIV infection risk and enriching public health education about HIV and ARVs to improve perceptions about people with HIV.

Cellular Mechanism of Inner Ear Genetic Disease, roles of Kv7.1 (KCNQ1) Channel

NASA Astrophysics Data System (ADS)

Mousavi Nik, Atefeh

Potassium channels are the most diverse and widely distributed membrane protein in all living organisms. They have various roles in the body such as controlling membrane potential, cell volume, and cell migration. Many studies have shown that mutation in these channels is associated with different diseases for example: Hearing Defect, Cardiac Arrhythmia, Episodic Ataxia, Seizure and Neuromyotonia. One of the most important diseases associated with K+ channel mutations is called Jervell and Lange-Nielsen syndrome (JLNS). This disease causes bilateral congenital deafness and the patients also suffer from Long QT and they usually experience syncopal episodes in their life and eventually die as a result of cardiac arrest. The gene KCNQ1 encodes the Kv7.1 voltage gated potassium channel. This channel expresses in apical membrane of marginal cell in stria vasularis of cochlea and secret K+ ion to endolymp to keep the endocochlear potential stable, which is necessary for the inner ear to function properly. Kv7.1 channel also expresses in cardiac myocytes and mutation in this gene is associated with another syndrome called Romano-Ward syndrome (RWS). Although Romano-Ward patients have mutation in KCNQ1, similar to Jervell and Lange-Nielsen patients, they only suffer from cardiac defect, and their hearing is completely normal. Several studies identified that mutations in Kv7.1 gene is associated with JLNS and RWS, but the biophysical and cellular mechanisms of these mutations are still unknown. To determine the cellular mechanisms of JLNS and RWS, and to provide mechanistic insight on the functional outputs of JLNS versus RWS mutations, we generated several mutant forms of the human Kv7.1 ( KCNQ1) clone, using site-directed mutagenesis to define their sub-cellular localization and examined their electrophysiological properties. We identified JLNS and RWS mutations at the S4-S5-linker, the pore loop (P-loop) and the C-terminus of hKv7.1 which have been found to control channel gating, permeation and modulation, respectively. The result showed that for JLNS, all P-loop and C-terminal mutations (seven mutations) yielded non-functional channels when expressed alone. Moreover, the W248F at the end of the S4 domain yielded a functional current, but it became inactivated at positive step potentials, therefore the channel essentially is non-functional. All the JLNS mutant channels are non-functional, and have impaired membrane trafficking. In contrast, the RWS mutants showed wide-ranging functional phenotypes consisting of channels with large current, channel with no measurable current when expressed alone, but significant current upon addition of the WT subunit and finally channel with no measurable current even in presence of WT subunit. The RWS mutants, however, produced dominant negative effect. These findings provide integrated cellular and molecular mechanisms of hKv7.1 functions and the consequent diseased phenotype in JLNS and RWS may come from the tissue-specific function of the channel.

Gaining Options: A Mathematics Program for Potentially Talented At-Risk Adolescent Girls

ERIC Educational Resources Information Center

Reid, Pamela Trotman; Roberts, Sally K.

2006-01-01

In response to indicators that a decline in interest in mathematics occurs among girls--particularly those from low-income and minority groups--during middle school, the GO-GIRL (Gaining Options: Girls Investigate Real Life) program was designed to help potentially talented at-risk girls. The program aimed to build mathematical confidence, skills,…

Do biological and bedsite characteristics influence survival of neonatal white-tailed deer?

Treesearch

M. Colter Chitwood; Marcus A. Lashley; John C. Kilgo; Kenneth H. Pollock; Christopher E. Moorman; Christopher S. DePerno

2015-01-01

Coyotes recently expanded into the eastern U.S. and potentially have caused localized white-tailed deer population declines. Research has focused on quantifying coyote predation on neonates, but little research has addressed the potential influence of bedsite characteristics on survival. In 2011 and 2012, we radiocollared 65 neonates, monitored them intensively for 16...

Capitalizing on the Potential of Minnesota's Rural Campuses. Seeking Solutions for Greater Minnesota's Future

ERIC Educational Resources Information Center

Manning, Monica M.; Campbell, Candace; Triplett, Thomas J.

2004-01-01

Rural regions across the nation are threatened by declining populations, slowing economies, and legislative power transfers to urban and suburban regions. The very survival of colleges located in these rural regions is at stake. The potential for these rural campuses to survive and thrive via more far-reaching collaboration with their communities…

Early Decline in Glucose Transport and Metabolism Precedes Shift to Ketogenic System in Female Aging and Alzheimer's Mouse Brain: Implication for Bioenergetic Intervention

PubMed Central

Ding, Fan; Yao, Jia; Rettberg, Jamaica R.; Chen, Shuhua; Brinton, Roberta Diaz

2013-01-01

We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3–15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6–9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential targets for preventing shifts to less efficient bioenergetic fuels and transition to the ketogenic phenotype of the Alzheimer's brain. PMID:24244584

Dropping dead: causes and consequences of vulture population declines worldwide.

PubMed

Ogada, Darcy L; Keesing, Felicia; Virani, Munir Z

2012-02-01

Vultures are nature's most successful scavengers, and they provide an array of ecological, economic, and cultural services. As the only known obligate scavengers, vultures are uniquely adapted to a scavenging lifestyle. Vultures' unique adaptations include soaring flight, keen eyesight, and extremely low pH levels in their stomachs. Presently, 14 of 23 (61%) vulture species worldwide are threatened with extinction, and the most rapid declines have occurred in the vulture-rich regions of Asia and Africa. The reasons for the population declines are varied, but poisoning or human persecution, or both, feature in the list of nearly every declining species. Deliberate poisoning of carnivores is likely the most widespread cause of vulture poisoning. In Asia, Gyps vultures have declined by >95% due to poisoning by the veterinary drug diclofenac, which was banned by regional governments in 2006. Human persecution of vultures has occurred for centuries, and shooting and deliberate poisoning are the most widely practiced activities. Ecological consequences of vulture declines include changes in community composition of scavengers at carcasses and an increased potential for disease transmission between mammalian scavengers at carcasses. There have been cultural and economic costs of vulture declines as well, particularly in Asia. In the wake of catastrophic vulture declines in Asia, regional governments, the international scientific and donor communities, and the media have given the crisis substantial attention. Even though the Asian vulture crisis focused attention on the plight of vultures worldwide, the situation for African vultures has received relatively little attention especially given the similar levels of population decline. While the Asian crisis has been largely linked to poisoning by diclofenac, vulture population declines in Africa have numerous causes, which have made conserving existing populations more difficult. And in Africa there has been little government support to conserve vultures despite mounting evidence of the major threats. In other regions with successful vulture conservation programs, a common theme is a huge investment of financial resources and highly skilled personnel, as well as political will and community support. © 2012 New York Academy of Sciences.

Measles, mumps, and rubella antibody patterns of persistence and rate of decline following the second dose of the MMR vaccine.

PubMed

Seagle, Emma E; Bednarczyk, Robert A; Hill, Tenisha; Fiebelkorn, Amy Parker; Hickman, Carole J; Icenogle, Joseph P; Belongia, Edward A; McLean, Huong Q

2018-02-01

Antibodies to measles, mumps, and rubella decline 3% per year on average, and have a high degree of individual variation. Yet, individual variations and differences across antigens are not well understood. To better understand potential implications on individual and population susceptibility, we reanalyzed longitudinal data to identify patterns of seropositivity and persistence. Children vaccinated with the second dose of measles, mumps, rubella vaccine (MMR2) at 4-6 years of age were followed up to 12 years post-vaccination. The rates of antibody decline were assessed using regression models, accounting for differences between and within subjects. Most of the 302 participants were seropositive throughout follow-up (96% measles, 88% mumps, 79% rubella). The rate of antibody decline was associated with MMR2 response and baseline titer for measles and age at first dose of MMR (MMR1) for rubella. No demographic or clinical factors were associated with mumps rate of decline. One month post-MMR2, geometric mean titer (GMT) to measles was high (3892 mIU/mL), but declined on average 9.7% per year among those with the same baseline titer and <2-fold increase post-MMR2. Subjects with ≥2-fold experienced a slower decline (≤7.4%). GMT to rubella was 149 one month post-MMR2, declining 2.6% and 5.9% per year among those who received MMR1 at 12-15 months and >15 months, respectively. GMT to mumps one month post-MMR2 was 151, declining 9.2% per year. Only 14% of subjects had the same persistence trends for all antigens. The rate of antibody decay varied substantially among individuals and the 3 antigen groups. A fast rate of decline coupled with high variation was observed for mumps, yet no predictors were identified. Future research should focus on better understanding waning titers to mumps and its impacts on community protection and individual susceptibility, in light of recent outbreaks in vaccinated populations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impaired haemophilus influenzae type b transplacental antibody transmission and declining antibody avidity through the first year of life represent potential vulnerabilities for HIV-exposed but -uninfected infants.

PubMed

Gaensbauer, James T; Rakhola, Jeremy T; Onyango-Makumbi, Carolyne; Mubiru, Michael; Westcott, Jamie E; Krebs, Nancy F; Asturias, Edwin J; Fowler, Mary Glenn; McFarland, Elizabeth; Janoff, Edward N

2014-12-01

To determine whether immune function is impaired among HIV-exposed but -uninfected (HEU) infants born to HIV-infected mothers and to identify potential vulnerabilities to vaccine-preventable infection, we characterized the mother-to-infant placental transfer of Haemophilus influenzae type b-specific IgG (Hib-IgG) and its levels and avidity after vaccination in Ugandan HEU infants and in HIV-unexposed U.S. infants. Hib-IgG was measured by enzyme-linked immunosorbent assay in 57 Ugandan HIV-infected mothers prenatally and in their vaccinated HEU infants and 14 HIV-unexposed U.S. infants at birth and 12, 24, and 48 weeks of age. Antibody avidity at birth and 48 weeks of age was determined with 1 M ammonium thiocyanate. A median of 43% of maternal Hib-IgG was transferred to HEU infants. Although its level was lower in HEU infants than in U.S. infants at birth (P < 0.001), Hib-IgG was present at protective levels (>1.0 μg/ml) at birth in 90% of HEU infants and all U.S. infants. HEU infants had robust Hib-IgG responses to a primary vaccination. Although Hib-IgG levels declined from 24 to 48 weeks of age in HEU infants, they were higher than those in U.S. infants (P = 0.002). Antibody avidity, comparable at birth, declined by 48 weeks of age in both populations. Early vaccination of HEU infants may limit an initial vulnerability to Hib disease resulting from impaired transplacental antibody transfer. While initial Hib vaccine responses appeared adequate, the confluence of lower antibody avidity and declining Hib-IgG levels in HEU infants by 12 months support Hib booster vaccination at 1 year. Potential immunologic impairments of HEU infants should be considered in the development of vaccine platforms for populations with high maternal HIV prevalence. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales.

PubMed

Stickler, Claudia M; Coe, Michael T; Costa, Marcos H; Nepstad, Daniel C; McGrath, David G; Dias, Livia C P; Rodrigues, Hermann O; Soares-Filho, Britaldo S

2013-06-04

Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations' energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local "direct" effects (through changes in ET within the watershed) and the potential regional "indirect" effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world's largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4-8% and 10-12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6-36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry's own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests.

Phytoremediation potential of some halophytic species for soil salinity.

PubMed

Devi, S; Nandwal, A S; Angrish, R; Arya, S S; Kumar, N; Sharma, S K

2016-01-01

Phytoremediation potential of six halophytic species i.e. Suaeda nudiflora, Suaeda fruticosa, Portulaca oleracea, Atriplex lentiformis, Parkinsonia aculeata and Xanthium strumarium was assessed under screen house conditions. Plants were raised at 8.0, 12.0, 16.0, and 20.0 dSm(-1) of chloride-dominated salinity. The control plants were irrigated with canal water. Sampling was done at vegetative stage (60-75 DAS). About 95 percent seed germination occurred up to 12 dSm(-1) and thereafter declined slightly. Mean plant height and dry weight plant(-1) were significantly decreased from 48.71 to 32.44 cm and from 1.73 to 0.61g plant(-1) respectively upon salinization. Na(+)/K(+) ratio (0.87 to 2.72), Na(+)/ Ca(2+) + Mg(2+) (0.48 to 1.54) and Cl(-)/SO4(2-) (0.94 to 5.04) ratio showed increasing trend. Salinity susceptibility index was found minimum in Suaeda fruticosa (0.72) and maximum in Parkinsonia aculeata (1.17). Total ionic content also declined and magnitude of decline varied from 8.51 to 18.91% at 8 dSm(-1) and 1.85 to 7.12% at 20 dSm(-1) of salinity. On the basis of phytoremediation potential Suaeda fruticosa (1170.02 mg plant(-1)), Atriplex lentiformis (777.87 mg plant(-1)) were the best salt hyperaccumulator plants whereas Xanthium strumarium (349.61 mg plant(-1)) and Parkinsonia aculeata (310.59 mg plant(-1)) were the least hyperaccumulator plants.

Opportunity for peri-urban Perth groundwater trade

NASA Astrophysics Data System (ADS)

Gao, Lei; Connor, Jeff; Doble, Rebecca; Ali, Riasat; McFarlane, Don

2013-07-01

Groundwater trade is widely advocated for reallocating scarce groundwater resources between competing users, and managing over-allocated and declining aquifers. However, groundwater markets are still in their infancy, and the potential benefits and opportunities need investigation, particularly where there is a need to reduce the extraction from declining aquifers. This article evaluates economic impacts of reducing groundwater extraction for irrigation use in peri-urban Perth, Australia, where irrigation, a lake-based ecosystem, and public water supply are highly dependent on a declining groundwater resource. We present an assessment of market-based water trading approaches to reduce groundwater extraction with an economic model representing diversity in returns to groundwater use across a population of irrigators. The results indicate that potential economic costs of a proportional reduction in available groundwater for irrigation are 18-21% less if groundwater trade is possible. We also evaluate a water buyback from irrigation to provide public water supply as an alternative to new infrastructure. We find that buying back up to around 50% of current irrigation allocations could create new public water supply only at the cost of 0.32-0.39 million per GL, which is less than one fifth of the costs of new desalinisation or recycled water supply options (2-3 million per GL). We conclude that, with rapid development of computer and internet based trading platforms that allows fast, efficient and low cost multiple party trading, it is increasingly feasible to realise the economic potentials of market-based trade approaches for managing overexploited aquifers.

Age-related decline in ovarian follicle stocks differ between chimpanzees (Pan troglodytes) and humans.

PubMed

Cloutier, Christina T; Coxworth, James E; Hawkes, Kristen

2015-02-01

Similarity in oldest parturitions in humans and great apes suggests that we maintain ancestral rates of ovarian aging. Consistent with that hypothesis, previous counts of primordial follicles in postmortem ovarian sections from chimpanzees (Pan troglodytes) showed follicle stock decline at the same rate that human stocks decline across the same ages. Here, we correct that finding with a chimpanzee sample more than three times larger than the previous one, which also allows comparison into older ages. Analyses show depletion rates similar until about age 35, but after 35, the human counts continue to fall with age, while the change is much less steep in chimpanzees. This difference implicates likely effects on ovarian dynamics from other physiological systems that are senescing at different rates, and, potentially, different perimenopausal experience for chimpanzees and humans.

Hormones and immune function: implications of aging.

PubMed

Arlt, Wiebke; Hewison, Martin

2004-08-01

Aging is associated with a decline in immunity described as immunosenescence. This is paralleled by a decline in the production of several hormones, as typically illustrated by the menopausal loss of ovarian oestrogen production. However, other hormonal changes that occur with aging and that potentially impact on immune function include the release of the pineal gland hormone melatonin and pituitary growth hormone, adrenal production of dehydroepiandrosterone and tissue-specific availability of active vitamin D. It remains to be established whether hormonal changes with aging actually contribute to immunosenescence and this area is at the interface of fact and fiction, clearly inviting systematic research efforts. As a step in this direction, the present review summarizes established facts on the physiology of secretion and function of hormones that, in most cases, decline with aging and that are likely to affect the immune system.

Nanostructural control of methane release in kerogen and its implications to wellbore production decline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

In spite of the massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Here we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases, and we usemore » molecular simulations to demonstrate it. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Finally, our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.« less

The Potential Utility of Eye Movements in the Detection and Characterization of Everyday Functional Difficulties in Mild Cognitive Impairment.

PubMed

Seligman, Sarah C; Giovannetti, Tania

2015-06-01

Mild cognitive impairment (MCI) refers to the intermediate period between the typical cognitive decline of normal aging and more severe decline associated with dementia, and it is associated with greater risk for progression to dementia. Research has suggested that functional abilities are compromised in MCI, but the degree of impairment and underlying mechanisms remain poorly understood. The development of sensitive measures to assess subtle functional decline poses a major challenge for characterizing functional limitations in MCI. Eye-tracking methodology has been used to describe visual processes in everyday, naturalistic action among healthy older adults as well as several case studies of severely impaired individuals, and it has successfully differentiated healthy older adults from those with MCI on specific visual tasks. These studies highlight the promise of eye-tracking technology as a method to characterize subtle functional decline in MCI. However, to date no studies have examined visual behaviors during completion of naturalistic tasks in MCI. This review describes the current understanding of functional ability in MCI, summarizes findings of eye-tracking studies in healthy individuals, severe impairment, and MCI, and presents future research directions to aid with early identification and prevention of functional decline in disorders of aging.

Alterations in frontal white matter neurochemistry and microstructure in schizophrenia: implications for neuroinflammation.

PubMed

Chiappelli, J; Hong, L E; Wijtenburg, S A; Du, X; Gaston, F; Kochunov, P; Rowland, L M

2015-04-14

We investigated in vivo neurochemical markers reflective of neuronal health and glial activation to determine if these could yield clues regarding the reduced fractional anisotropy (FA) of white matter and accelerated decline of FA with age in schizophrenia. Participants with schizophrenia and healthy controls completed diffusion tensor imaging to assess FA and proton magnetic resonance spectroscopy to assess neurochemical metabolites in the same frontal region. Frontal FA was significantly lower in the schizophrenia and declined more rapidly with age compared with the healthy control group. In both groups, N-acetylaspartate (NAA), a putative marker of neuronal integrity, and glutamate declined with age, and this decline was stronger in patients. Myo-inositol, a marker of glial cells, was negatively related to FA in both groups. The relationship between FA and age remained significant in schizophrenia even when controlling for all metabolites. The relationships of FA, NAA and myo-inositol to age appear to be independent of one another. The relationship between FA and myo-inositol was independently present in both patients and controls, even after controlling for age, indicating a potential general effect of neuroinflammation on white matter microstructure. Further studies are warranted to determine the underlying mechanism driving the accelerated FA decline with age in schizophrenia.

Climate and ecosystem linkages explain widespread declines in North American Atlantic salmon populations.

PubMed

Mills, Katherine E; Pershing, Andrew J; Sheehan, Timothy F; Mountain, David

2013-10-01

North American Atlantic salmon (Salmo salar) populations experienced substantial declines in the early 1990s, and many populations have persisted at low abundances in recent years. Abundance and productivity declined in a coherent manner across major regions of North America, and this coherence points toward a potential shift in marine survivorship, rather than local, river-specific factors. The major declines in Atlantic salmon populations occurred against a backdrop of physical and biological shifts in Northwest Atlantic ecosystems. Analyses of changes in climate, physical, and lower trophic level biological factors provide substantial evidence that climate conditions directly and indirectly influence the abundance and productivity of North American Atlantic salmon populations. A major decline in salmon abundance after 1990 was preceded by a series of changes across multiple levels of the ecosystem, and a subsequent population change in 1997, primarily related to salmon productivity, followed an unusually low NAO event. Pairwise correlations further demonstrate that climate and physical conditions are associated with changes in plankton communities and prey availability, which are ultimately linked to Atlantic salmon populations. Results suggest that poor trophic conditions, likely due to climate-driven environmental factors, and warmer ocean temperatures throughout their marine habitat area are constraining the productivity and recovery of North American Atlantic salmon populations. © 2013 John Wiley & Sons Ltd.

Losing grip: Senescent decline in physical strength in a small-bodied primate in captivity and in the wild.

PubMed

Hämäläinen, Anni; Dammhahn, Melanie; Aujard, Fabienne; Kraus, Cornelia

2015-01-01

Muscle strength reflects physical functioning, declines at old age and predicts health and survival in humans and laboratory animals. Age-associated muscle deterioration causes loss of strength and may impair fitness of wild animals. However, the effects of age and life-history characteristics on muscle strength in wild animals are unknown. We investigated environment- and sex-specific patterns of physical functioning by measuring grip strength in wild and captive gray mouse lemurs. We expected more pronounced strength senescence in captivity due to condition-dependent, extrinsic mortality found in nature. Males were predicted to be stronger but potentially experience more severe senescence than females as predicted by life history theory. We found similar senescent declines in captive males and females as well as wild females, whereas wild males showed little decline, presumably due to their early mortality. Captive animals were generally weaker and showed earlier declines than wild animals. Unexpectedly, females tended to be stronger than males, especially in the reproductive season. Universal intrinsic mechanisms (e.g. sarcopenia) likely cause the similar patterns of strength loss across settings. The female advantage in muscle strength merits further study; it may follow higher reproductive investment by males, or be an adaptation associated with female social dominance. Copyright © 2014 Elsevier Inc. All rights reserved.

Hydraulics play an important role in causing low growth rate and dieback of aging Pinus sylvestris var. mongolica trees in plantations of Northeast China.

PubMed

Liu, Yan-Yan; Wang, Ai-Ying; An, Yu-Ning; Lian, Pei-Yong; Wu, De-Dong; Zhu, Jiao-Jun; Meinzer, Frederick C; Hao, Guang-You

2018-07-01

The frequently observed forest decline in water-limited regions may be associated with impaired tree hydraulics, but the precise physiological mechanisms remain poorly understood. We compared hydraulic architecture of Mongolian pine (Pinus sylvestris var. mongolica) trees of different size classes from a plantation and a natural forest site to test whether greater hydraulic limitation with increasing size plays an important role in tree decline observed in the more water-limited plantation site. We found that trees from plantations overall showed significantly lower stem hydraulic efficiency. More importantly, plantation-grown trees showed significant declines in stem hydraulic conductivity and hydraulic safety margins as well as syndromes of stronger drought stress with increasing size, whereas no such trends were observed at the natural forest site. Most notably, the leaf to sapwood area ratio (LA/SA) showed a strong linear decline with increasing tree size at the plantation site. Although compensatory adjustments in LA/SA may mitigate the effect of increased water stress in larger trees, they may result in greater risk of carbon imbalance, eventually limiting tree growth at the plantation site. Our results provide a potential mechanistic explanation for the widespread decline of Mongolian pine trees in plantations of Northern China. © 2018 John Wiley & Sons Ltd.

Nanostructural control of methane release in kerogen and its implications to wellbore production decline

PubMed Central

Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

2016-01-01

Despite massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Using molecular simulations, we here show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release. PMID:27306967

Nanostructural control of methane release in kerogen and its implications to wellbore production decline

DOE PAGES

Ho, Tuan Anh; Criscenti, Louise J.; Wang, Yifeng

2016-06-16

In spite of the massive success of shale gas production in the US in the last few decades there are still major concerns with the steep decline in wellbore production and the large uncertainty in a long-term projection of decline curves. A reliable projection must rely on a mechanistic understanding of methane release in shale matrix–a limiting step in shale gas extraction. Here we show that methane release in nanoporous kerogen matrix is characterized by fast release of pressurized free gas (accounting for ~30–47% recovery) followed by slow release of adsorbed gas as the gas pressure decreases, and we usemore » molecular simulations to demonstrate it. The first stage is driven by the gas pressure gradient while the second stage is controlled by gas desorption and diffusion. We further show that diffusion of all methane in nanoporous kerogen behaves differently from the bulk phase, with much smaller diffusion coefficients. The MD simulations also indicate that a significant fraction (3–35%) of methane deposited in kerogen can potentially become trapped in isolated nanopores and thus not recoverable. Finally, our results shed a new light on mechanistic understanding gas release and production decline in unconventional reservoirs. The long-term production decline appears controlled by the second stage of gas release.« less

Honey Bee Gut Microbiome Is Altered by In-Hive Pesticide Exposures.

PubMed

Kakumanu, Madhavi L; Reeves, Alison M; Anderson, Troy D; Rodrigues, Richard R; Williams, Mark A

2016-01-01

Honey bees (Apis mellifera) are the primary pollinators of major horticultural crops. Over the last few decades, a substantial decline in honey bees and their colonies have been reported. While a plethora of factors could contribute to the putative decline, pathogens, and pesticides are common concerns that draw attention. In addition to potential direct effects on honey bees, indirect pesticide effects could include alteration of essential gut microbial communities and symbionts that are important to honey bee health (e.g., immune system). The primary objective of this study was to determine the microbiome associated with honey bees exposed to commonly used in-hive pesticides: coumaphos, tau-fluvalinate, and chlorothalonil. Treatments were replicated at three independent locations near Blacksburg Virginia, and included a no-pesticide amended control at each location. The microbiome was characterized through pyrosequencing of V2-V3 regions of the bacterial 16S rRNA gene and fungal ITS region. Pesticide exposure significantly affected the structure of bacterial but not fungal communities. The bee bacteriome, similar to other studies, was dominated by sequences derived from Bacilli, Actinobacteria, α-, β-, γ-proteobacteria. The fungal community sequences were dominated by Ascomycetes and Basidiomycetes. The Multi-response permutation procedures (MRPP) and subsequent Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis indicated that chlorothalonil caused significant change to the structure and functional potential of the honey bee gut bacterial community relative to control. Putative genes for oxidative phosphorylation, for example, increased while sugar metabolism and peptidase potential declined in the microbiome of chlorothalonil exposed bees. The results of this field-based study suggest the potential for pesticide induced changes to the honey bee gut microbiome that warrant further investigation.

Association between age associated cognitive decline and health related quality of life among Iranian older individuals.

PubMed

Kazazi, Leila; Foroughan, Mahshid; Nejati, Vahid; Shati, Mohsen

2018-04-01

Age associated cognitive decline or normal cognitive aging is related with lower levels of functioning in real life, and may interfere with maintaining independence and health related quality of life (HRQL). In this study, health related quality of life and cognitive function in community-dwelling older adults were evaluated with the aim of exploring the association between them by adjusting for potential confounders. This cross-sectional study, was implemented on 425 community-dwelling older adults aged 60 and over, between August 2016 and October 2016 in health centers of the municipality of Tehran, Iran, using Mini Mental State Examination (MMSE) to assess cognitive function and Short Form-36 scales (SF-36) to assess HRQL. The relation between HRQL and cognitive function was evaluated by Pearson's correlation coefficient, and the impact of cognitive function on HRQL adjusted for potential confounders was estimated by linear regression model. All analyses were done using SPSS, version 22.0. A positive significant correlation between cognitive function and quality of life (r=0.434; p<0.001) and its dimensions was observed. Two variables of educational level (B=2.704; 95% CI: 2.09 to 3.30; p<0.001) and depression (B=2.554; 95% CI: 2.00 to 3.10; p<0.001) were assumed as potential confounder by changing effect measure after entering the model. After adjusting for potential confounders in regression model, the association between MMSE scores and quality of life persisted (B=2.417; 95% CI: 1.86 to 2.96; p<0.001). The results indicate that cognitive function was associated with HRQL in older adults with age associated cognitive function. Two variables of educational level and depression can affect the relation between cognitive decline and HRQL.

Honey Bee Gut Microbiome Is Altered by In-Hive Pesticide Exposures

PubMed Central

Kakumanu, Madhavi L.; Reeves, Alison M.; Anderson, Troy D.; Rodrigues, Richard R.; Williams, Mark A.

2016-01-01

Honey bees (Apis mellifera) are the primary pollinators of major horticultural crops. Over the last few decades, a substantial decline in honey bees and their colonies have been reported. While a plethora of factors could contribute to the putative decline, pathogens, and pesticides are common concerns that draw attention. In addition to potential direct effects on honey bees, indirect pesticide effects could include alteration of essential gut microbial communities and symbionts that are important to honey bee health (e.g., immune system). The primary objective of this study was to determine the microbiome associated with honey bees exposed to commonly used in-hive pesticides: coumaphos, tau-fluvalinate, and chlorothalonil. Treatments were replicated at three independent locations near Blacksburg Virginia, and included a no-pesticide amended control at each location. The microbiome was characterized through pyrosequencing of V2–V3 regions of the bacterial 16S rRNA gene and fungal ITS region. Pesticide exposure significantly affected the structure of bacterial but not fungal communities. The bee bacteriome, similar to other studies, was dominated by sequences derived from Bacilli, Actinobacteria, α-, β-, γ-proteobacteria. The fungal community sequences were dominated by Ascomycetes and Basidiomycetes. The Multi-response permutation procedures (MRPP) and subsequent Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis indicated that chlorothalonil caused significant change to the structure and functional potential of the honey bee gut bacterial community relative to control. Putative genes for oxidative phosphorylation, for example, increased while sugar metabolism and peptidase potential declined in the microbiome of chlorothalonil exposed bees. The results of this field-based study suggest the potential for pesticide induced changes to the honey bee gut microbiome that warrant further investigation. PMID:27579024

Leaf hydraulic conductance, measured in situ, declines and recovers daily: leaf hydraulics, water potential and stomatal conductance in four temperate and three tropical tree species

Treesearch

Daniel M. Johnson; David R. Woodruff; Katherien A. McCulloh; Frederick C. Meinzer

2009-01-01

The objectives of this study were to measure Kleaf, using a rehydration kinetics method, (1) in the laboratory (under controlled conditions) across a range of water potentials to construct vulnerability curves (VC) and (2) over the course of the day in the field along with leaf water potential and stomatal conductance. The results presented here...

Using interrupted time series design to analyze changes in hand, foot, and mouth disease incidence during the declining incidence periods of 2008-2010 in China.

PubMed

Yu, Shi Cheng; Hao, Yuan Tao; Zhang, Jing; Xiao, Ge Xin; Liu, Zhuang; Zhu, Qi; Ma, Jia Qi; Wang, Yu

2012-12-01

To identify patterns of hand, foot and mouth disease (HFMD) incidence in China during declining incidence periods of 2008, 2009, and 2010. Reported HFMD cases over a period of 25 months were extracted from the National Disease Reporting System (NDRS) and analyzed. An interrupted time series (ITS) technique was used to detect changes in HFMD incidence rates in terms of level and slope between declining incidence periods of the three years. Over 3.58 million HFMD cases younger than 5 years were reported to the NDRS between May 1, 2008, and May 31, 2011. Males comprised 63.4% of the cases. ITS analyses demonstrated a significant increase in incidence rate level (P<0.0001) when comparing the current period with the previous period. There were significant changes in declining slopes when comparing 2010 to 2009, and 2010 to 2008 (all P<0.005), but not 2009 to 2008. Incremental changes in incidence rate level during the declining incidence periods of 2009 and 2010 can potentially be attributed to a few factors. The more steeply declining slope in 2010 compared with previous years could be ascribed to the implementation of more effective interventions and preventive strategies in 2010. Further investigation is required to examine this possibility. Copyright © 2012 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

Effect of Early Referral to Specialist in Dementia on Institutionalization and Functional Decline: Findings from a Population-Based Study.

PubMed

Pimouguet, Clément; Le-Goff, Mélanie; Rizzuto, Debora; Berr, Claudine; Leffondré, Karen; Pérès, Karine; Dartigues, Jean FranÇois; Helmer, Catherine

2016-01-01

Although early diagnosis has been hypothesized to benefit both patients and caregivers, until now studies evaluating the effect of early dementia diagnosis are lacking. To investigate the influence of early specialist referral for dementia on the risk of institutionalization and functional decline in Activity of Daily Living (ADL). Incident dementia cases were screened in a prospective population-based cohort, the Three-City Study, and initial specialist consultation for cognitive complaint was assessed at dementia diagnosis. Proportional hazard regression and illness-death models were used to test the association between specialist referral and, respectively, institutionalization and functional decline. Only one third of the incident individuals with dementia had consulted a specialist for cognitive problems early (36%). After adjustment on potential confounders (including cognitive and functional decline) and competing risk of death, participants who had consulted a specialist early in the disease course presented a higher rate of being institutionalized than those who did not (Hazard Ratio = 2.00, 95% Confidence Interval (CI): 1.09- 3.64). But early specialist referral was not associated with further functional decline (HR = 1.09, 95% CI: 0.71- 1.67). Early specialist referral in dementia is associated with increased risk of institutionalization but not with functional decline in ADL. These findings suggest that early care referral in dementia may be a marker of concern for patients and/or caregivers; subsequent medical and social care could be suboptimal or inappropriate to allow patients to stay longer at home.

Exposure of harbour seals Phoca vitulina to Brucella in declining populations across Scotland.

PubMed

Kershaw, Joanna L; Stubberfield, Emma J; Foster, Geoffrey; Brownlow, Andrew; Hall, Ailsa J; Perrett, Lorraine L

2017-09-20

Since 2000 there has been a major decline in the abundance of Scottish harbour seals Phoca vitulina. The causes of the decline remain uncertain. The aim of this study was to establish the extent to which the seals in the regions of greatest decline have been exposed to Brucella, a bacterial pathogen that causes reproductive failure in terrestrial mammalian hosts. Tissues from dead seals collected between 1992 and 2013 were cultured for Brucella (n = 150). Serum samples collected from live capture-released seals (n = 343) between 1997 and 2012 were tested for Brucella antibodies using the Rose Bengal plate agglutination test (RBT) and a competitive enzyme-linked immunosorbent assay (cELISA). In total, 16% of seals cultured had Brucella isolated from one or more tissues, but there were no pathological signs of infection. The cELISA results were more sensitive than the RBT results, showing that overall 25.4% of seals were seropositive, with the highest seroprevalence in juveniles. As there was no evidence of either a higher seroprevalence or higher circulating antibody levels in seropositive animals in the areas with the greatest declines, it was concluded that Brucella infection is likely not a major contributing factor to recent declines. However, the consistently high proportion of seals exposed to Brucella indicates possible endemicity in these populations, likely due to B. pinnipedialis, which has demonstrated a preference for pinniped hosts. Importantly, given the close proximity between seals, humans and livestock in many areas, there is the potential for cross-species infections.

Test of the invasive pathogen hypothesis of bumble bee decline in North America.

PubMed

Cameron, Sydney A; Lim, Haw Chuan; Lozier, Jeffrey D; Duennes, Michelle A; Thorp, Robbin

2016-04-19

Emergent fungal diseases are critical factors in global biodiversity declines. The fungal pathogenNosema bombiwas recently found to be widespread in declining species of North American bumble bees (Bombus), with circumstantial evidence suggesting an exotic introduction from Europe. This interpretation has been hampered by a lack of knowledge of global genetic variation, geographic origin, and changing prevalence patterns ofN. bombiin declining North American populations. Thus, the temporal and spatial emergence ofN. bombiand its potential role in bumble bee decline remain speculative. We analyzeNosemaprevalence and genetic variation in the United States and Europe from 1980, before an alleged introduction in the early 1990s, to 2011, extractingNosemaDNA fromBombusnatural history collection specimens from across this time period.Nosema bombiprevalence increased significantly from low detectable frequency in the 1980s to significantly higher frequency in the mid- to late-1990s, corresponding to a period of reported massive infectious outbreak ofN. bombiin commercial bumble bee rearing stocks in North America. Despite the increased frequency, we find no conclusive evidence of an exoticN. bombiorigin based on genetic analysis of globalNosemapopulations; the widespreadNosemastrain found currently in declining United States bumble bees was present in the United States before commercial colony trade. Notably, the USN. bombiis not detectably different from that found predominantly throughout Western Europe, with both regions characterized by low genetic diversity compared with high levels of diversity found in Asia, where commercial bee breeding activities are low or nonexistent.

Assessing the Factors of Regional Growth Decline of Sugar Maple

NASA Astrophysics Data System (ADS)

Bishop, D. A.; Beier, C. M.; Pederson, N.; Lawrence, G. B.; Stella, J. C.; Sullivan, T. J.

2014-12-01

Sugar maple (Acer saccharum Marsh) is among the most ecologically, economically and culturally important trees in North America, but has experienced a decline disease across much of its range. We investigated the climatic and edaphic factors associated with A. saccharum growth in the Adirondack Mountains (USA) using a well-replicated tree-ring network incorporating a range of soil fertility (base cation availability). We found that nearly 3 in 4 A. saccharum trees exhibited declining growth rates during the last several decades, regardless of tree age or size. Although diameter growth was consistently higher on base-rich soils, the negative trends in growth were largely consistent across the soil chemistry gradient. Sensitivity of sugar maple growth to climatic variability was overall weaker than expected, but were also non-stationary during the 20th century. We observed increasingly positive responses to late-winter precipitation, increasingly negative responses to growing season temperatures, and strong positive responses to moisture availability during the 1960s drought that became much weaker during the recent pluvial. Further study is needed of these factors and their interactions as potential mechanisms for sugar maple growth decline.

Better Cognitive Performance in Elderly Taking Antioxidant Vitamins E and C Supplements in Combination with NSAIDs: The Cache County Study

PubMed Central

Fotuhi, Majid; Zandi, Peter P.; Hayden, Kathleen M.; Khachaturian, Ara S.; Szekely, Christine A.; Wengreen, Heidi; Munger, Ronald G.; Norton, Maria C.; Tschanz, JoAnn T.; Lyketsos, Constantine G.; Breitner, John C.S.; Welsh-Bohmer, Kathleen A.

2009-01-01

Studies have shown less cognitive decline and lower risk of Alzheimer's disease in elderly individuals consuming either antioxidant vitamins or non-steroidal anti-inflammatory drugs (NSAIDs). The potential of added benefit from their combined use has not been studied. We therefore analyzed data from 3,376 elderly participants of the Cache County Study who were given the Modified Mini-Mental State (3MS) examination up to three times over eight years. Those who used a combination of Vitamins E and C supplements and NSAIDs at baseline declined by an average 0.96 fewer points every 3 years than non-users (p<0.05). This apparent effect was attributable entirely to participants with the APOE ε4 allele, whose users declined by 2.25 fewer points than non-users every 3 years (p<0.05). These results suggest that among elderly individuals with an APOE ε4 allele, there is an association between using antioxidant supplements in combination with NSAIDs and less cognitive decline over time. PMID:18631971

Voluntary running, skeletal muscle gene expression, and signaling inversely regulated by orchidectomy and testosterone replacement.

PubMed

Ibebunjo, Chikwendu; Eash, John K; Li, Christine; Ma, QiCheng; Glass, David J

2011-02-01

Declines in skeletal muscle size and strength, often seen with chronic wasting diseases, prolonged or high-dose glucocorticoid therapy, and the natural aging process in mammals, are usually associated with reduced physical activity and testosterone levels. However, it is not clear whether the decline in testosterone and activity are causally related. Using a mouse model, we found that removal of endogenous testosterone by orchidectomy results in an almost complete cessation in voluntary wheel running but only a small decline in muscle mass. Testosterone replacement restored running behavior and muscle mass to normal levels. Orchidectomy also suppressed the IGF-I/Akt pathway, activated the atrophy-inducing E3 ligases MuRF1 and MAFBx, and suppressed several energy metabolism pathways, and all of these effects were reversed by testosterone replacement. The study also delineated a distinct, previously unidentified set of genes that is inversely regulated by orchidectomy and testosterone treatment. These data demonstrate the necessity of testosterone for both speed and endurance of voluntary wheel running in mice and suggest a potential mechanism for declined activity in humans where androgens are deficient.

Creutzfeldt-Jakob Disease as a Cause of Cognitive Decline and Seizures in the Elderly: Diagnostic Pointers and Strategy for Investigation

PubMed Central

Williams, R.; Cresswell, F.; McClure, M.; Lane, R.

2011-01-01

Cognitive decline affects one in twenty people over the age of 65. There is often a paucity of clues as to the underlying pathology, and while the diagnosis will usually prove to be either Alzheimer's disease or vascular dementia, there may be clinical features suggesting rarer alternatives. This case of a 71-year-old lady with a 3-month history of progressive cognitive decline illustrates clinical features suggestive of Creutzfeltd-Jakob disease such as rapid decline in conscious level and myoclonic jerking. Diagnosis was confirmed by 3 means: (1) Electroencephalogram demonstrating periodic sharp wave complexes, (2) MRI brain showing cortical ribboning and high signal in the caudate nucleus, and (3) presence of protein S100 and protein14-3-3 in the cerebrospinal fluid. Postmortem brain histology confirmed a typical spongiform encephalopathy. Establishing an underlying aetiology is dementia is important not only for prognostic reasons but in order to detect potentially reversible causes. In cases of an atypical dementing illness our proposed investigations may assist in confirming or excluding underlying Creutzfeltd-Jakob disease. PMID:22194754

The Decline of Intergenerational Coresidence in the United States, 1850 to 2000

PubMed Central

Ruggles, Steven

2011-01-01

In the mid-nineteenth century, almost 70 percent of persons age 65 or older resided with their adult children; by the end of the twentieth century, fewer than 15 percent did so. Many scholars have argued that the simplification of the living arrangements of the aged resulted primarily from an increase in their resources, which enabled increasing numbers of elders to afford independent living. This article supports a different interpretation: the evidence suggests that the decline of coresidence between generations had less to do with the growing affluence of the aged than with the increasing opportunities of the younger generation. Using data from the Integrated Public Use Microdata Series (IPUMS), I examine long-run trends in the characteristics of both the older and the younger generations to gain insight into changing motivations for coresidence. In particular, I investigate headship patterns, occupational status, income, and spatial coresidence patterns. I also reassess the potential impact of the Social Security program. I conclude that the decline of intergenerational coresidence resulted mainly from increasing opportunities for the young and declining parental control over their children. PMID:21562613

Cognitive and behavioral assessment in dogs and pet food market applications.

PubMed

Zicker, Steven C

2005-03-01

A multi-disciplinary program was developed to assess the efficacy of antioxidant inclusion in a canine pet food on cognitive decline in aged beagles. A systematic approach to development of the food was used prior to beginning the cognitive studies. Comprehensive evaluation of antioxidant ingredients included assessments of commodities with naturally occurring antioxidants and synthetic antioxidants not commonly utilized, or at different concentrations than what was commonly utilized, in commercial pet foods. Studies were conducted to insure stability through processing, absorption from the gastrointestinal tract, safety, and tests for potential antioxidant biological benefit by ex vivo tests. Testing of the antioxidant-fortified food in aged beagles slowed the rate of cognitive decline in aged dogs. In addition, environmental enrichment also slowed the rate of cognitive decline. Importantly, the combination of dietary antioxidants and environmental enrichment was synergistic and resulted in the least amount of cognitive decline over the 30-month study period. Finally, a clinical study showed that antioxidant fortified food improved age-related behavioral changes in older pet dogs at in-home situations.

Genetic characterization of hybridization between native and invasive bittersweet vines (Celastrus spp.)

USGS Publications Warehouse

Zaya, David N.; Leicht-Young, Stacey A.; Pavlovic, Noel B.; Feldheim, Kevin A.; Ashley, Mary V.

2015-01-01

Hybridization associated with species introductions can accelerate the decline of native species. The main objective of this study was to determine if the decline of a North American liana (American bittersweet, Celastrus scandens) in the eastern portion of its range is related to hybridization with an introduced congener (oriental bittersweet, C. orbiculatus). We used newly characterized microsatellite loci, a maternally-inherited chloroplast DNA marker, and field observation to survey individuals across the USA to determine the prevalence of hybrids, their importance in the invasion of C. orbiculatus, and the predominant direction of hybridization. We found that only 8.4 % of non-native genotypes were hybrids (20 of 239), and these hybrids were geographically widespread. Hybrids showed reduced seed set (decline of >98 %) and small, likely inviable pollen. Genetic analysis of a maternally inherited chloroplast marker showed that all 20 identified hybrids came from C. scandens seed parents. The strong asymmetry in pollen flow that favors fecundity in introduced males has the potential to greatly accelerate the decline of native species by wasting limited female reproductive effort.

Sources of Disconnection in Neurocognitive Aging: Cerebral White Matter Integrity, Resting-state Functional Connectivity, and White Matter Hyperintensity Volume

PubMed Central

Madden, David J.; Parks, Emily L.; Tallman, Catherine W.; Boylan, Maria A.; Hoagey, David A.; Cocjin, Sally B.; Packard, Lauren E.; Johnson, Micah A.; Chou, Ying-hui; Potter, Guy G.; Chen, Nan-kuei; Siciliano, Rachel E.; Monge, Zachary A.; Honig, Jesse A.; Diaz, Michele T.

2017-01-01

Age-related decline in fluid cognition can be characterized as a disconnection among specific brain structures, leading to a decline in functional efficiency. The potential sources of disconnection, however, are unclear. We investigated imaging measures of cerebral white matter integrity, resting-state functional connectivity, and white matter hyperintensity (WMH) volume as mediators of the relation between age and fluid cognition, in 145 healthy, community-dwelling adults 19–79 years of age. At a general level of analysis, with a single composite measure of fluid cognition and single measures of each of the three imaging modalities, age exhibited an independent influence on the cognitive and imaging measures, and the imaging variables did not mediate the age-cognition relation. At a more specific level of analysis, resting-state functional connectivity of sensorimotor networks was a significant mediator of the age-related decline in executive function. These findings suggest that different levels of analysis lead to different models of neurocognitive disconnection, and that resting-state functional connectivity, in particular, may contribute to age-related decline in executive function. PMID:28389085

Increase of EEG Spectral Theta Power Indicates Higher Risk of the Development of Severe Cognitive Decline in Parkinson’s Disease after 3 Years

PubMed Central

Cozac, Vitalii V.; Chaturvedi, Menorca; Hatz, Florian; Meyer, Antonia; Fuhr, Peter; Gschwandtner, Ute

2016-01-01

Objective: We investigated quantitative electroencephalography (qEEG) and clinical parameters as potential risk factors of severe cognitive decline in Parkinson’s disease. Methods: We prospectively investigated 37 patients with Parkinson’s disease at baseline and follow-up (after 3 years). Patients had no severe cognitive impairment at baseline. We used a summary score of cognitive tests as the outcome at follow-up. At baseline we assessed motor, cognitive, and psychiatric factors; qEEG variables [global relative median power (GRMP) spectra] were obtained by a fully automated processing of high-resolution EEG (256-channels). We used linear regression models with calculation of the explained variance to evaluate the relation of baseline parameters with cognitive deterioration. Results: The following baseline parameters significantly predicted severe cognitive decline: GRMP theta (4–8 Hz), cognitive task performance in executive functions and working memory. Conclusions: Combination of neurocognitive tests and qEEG improves identification of patients with higher risk of cognitive decline in PD. PMID:27965571

Systemic Regulation of the Age-Related Decline of Pancreatic β-Cell Replication

PubMed Central

Salpeter, Seth J.; Khalaileh, Abed; Weinberg-Corem, Noa; Ziv, Oren; Glaser, Benjamin; Dor, Yuval

2013-01-01

The frequency of pancreatic β-cell replication declines dramatically with age, potentially contributing to the increased risk of type 2 diabetes in old age. Previous studies have shown the involvement of cell-autonomous factors in this phenomenon, particularly the decline of polycomb genes and accumulation of p16/INK4A. Here, we demonstrate that a systemic factor found in the circulation of young mice is able to increase the proliferation rate of old pancreatic β-cells. Old mice parabiosed to young mice have increased β-cell replication compared with unjoined old mice or old mice parabiosed to old mice. In addition, we demonstrate that old β-cells transplanted into young recipients have increased replication rate compared with cells transplanted into old recipients; conversely, young β-cells transplanted into old mice decrease their replication rate compared with young cells transplanted into young recipients. The expression of p16/INK4A mRNA did not change in heterochronic parabiosis, suggesting the involvement of other pathways. We conclude that systemic factors contribute to the replicative decline of old pancreatic β-cells. PMID:23630298

Age-associated Cognitive Decline: Insights into Molecular Switches and Recovery Avenues.

PubMed

Konar, Arpita; Singh, Padmanabh; Thakur, Mahendra K

2016-03-01

Age-associated cognitive decline is an inevitable phenomenon that predisposes individuals for neurological and psychiatric disorders eventually affecting the quality of life. Scientists have endeavored to identify the key molecular switches that drive cognitive decline with advancing age. These newly identified molecules are then targeted as recovery of cognitive aging and related disorders. Cognitive decline during aging is multi-factorial and amongst several factors influencing this trajectory, gene expression changes are pivotal. Identifying these genes would elucidate the neurobiological underpinnings as well as offer clues that make certain individuals resilient to withstand the inevitable age-related deteriorations. Our laboratory has focused on this aspect and investigated a wide spectrum of genes involved in crucial brain functions that attribute to senescence induced cognitive deficits. We have recently identified master switches in the epigenome regulating gene expression alteration during brain aging. Interestingly, these factors when manipulated by chemical or genetic strategies successfully reverse the age-related cognitive impairments. In the present article, we review findings from our laboratory and others combined with supporting literary evidences on molecular switches of brain aging and their potential as recovery targets.

Better cognitive performance in elderly taking antioxidant vitamins E and C supplements in combination with nonsteroidal anti-inflammatory drugs: the Cache County Study.

PubMed

Fotuhi, Majid; Zandi, Peter P; Hayden, Kathleen M; Khachaturian, Ara S; Szekely, Christine A; Wengreen, Heidi; Munger, Ronald G; Norton, Maria C; Tschanz, Joann T; Lyketsos, Constantine G; Breitner, John C S; Welsh-Bohmer, Kathleen

2008-05-01

Studies have shown less cognitive decline and lower risk of Alzheimer's disease in elderly individuals consuming either antioxidant vitamins or nonsteroidal anti-inflammatory drugs (NSAIDs). The potential of added benefit from their combined use has not been studied. We therefore analyzed data from 3,376 elderly participants of the Cache County Study who were given the Modified Mini-Mental State examination up to three times during a period of 8 years. Those who used a combination of vitamins E and C supplements and NSAIDs at baseline declined by an average 0.96 fewer points every 3 years than nonusers (P < .05). This apparent effect was attributable entirely to participants with the APOE epsilon4 allele, whose users declined by 2.25 fewer points than nonusers every 3 years (P < .05). These results suggest that among elderly individuals with an APOE epsilon4 allele, there is an association between using antioxidant supplements in combination with NSAIDs and less cognitive decline over time.

Evolving Evidence for the Value of Neuroimaging Methods and Biological Markers in Subjects Categorized with Subjective Cognitive Decline.

PubMed

Lista, Simone; Molinuevo, Jose L; Cavedo, Enrica; Rami, Lorena; Amouyel, Philippe; Teipel, Stefan J; Garaci, Francesco; Toschi, Nicola; Habert, Marie-Odile; Blennow, Kaj; Zetterberg, Henrik; O'Bryant, Sid E; Johnson, Leigh; Galluzzi, Samantha; Bokde, Arun L W; Broich, Karl; Herholz, Karl; Bakardjian, Hovagim; Dubois, Bruno; Jessen, Frank; Carrillo, Maria C; Aisen, Paul S; Hampel, Harald

2015-09-24

There is evolving evidence that individuals categorized with subjective cognitive decline (SCD) are potentially at higher risk for developing objective and progressive cognitive impairment compared to cognitively healthy individuals without apparent subjective complaints. Interestingly, SCD, during advancing preclinical Alzheimer's disease (AD), may denote very early, subtle cognitive decline that cannot be identified using established standardized tests of cognitive performance. The substantial heterogeneity of existing SCD-related research data has led the Subjective Cognitive Decline Initiative (SCD-I) to accomplish an international consensus on the definition of a conceptual research framework on SCD in preclinical AD. In the area of biological markers, the cerebrospinal fluid signature of AD has been reported to be more prevalent in subjects with SCD compared to healthy controls; moreover, there is a pronounced atrophy, as demonstrated by magnetic resonance imaging, and an increased hypometabolism, as revealed by positron emission tomography, in characteristic brain regions affected by AD. In addition, SCD individuals carrying an apolipoprotein ɛ4 allele are more likely to display AD-phenotypic alterations. The urgent requirement to detect and diagnose AD as early as possible has led to the critical examination of the diagnostic power of biological markers, neurophysiology, and neuroimaging methods for AD-related risk and clinical progression in individuals defined with SCD. Observational studies on the predictive value of SCD for developing AD may potentially be of practical value, and an evidence-based, validated, qualified, and fully operationalized concept may inform clinical diagnostic practice and guide earlier designs in future therapy trials.

Trypanosomes genetic diversity, polyparasitism and the population decline of the critically endangered Australian marsupial, the brush tailed bettong or woylie (Bettongia penicillata)

PubMed Central

Botero, Adriana; Thompson, Craig K.; Peacock, Christopher S.; Clode, Peta L.; Nicholls, Philip K.; Wayne, Adrian F.; Lymbery, Alan J.; Thompson, R.C. Andrew

2013-01-01

While much is known of the impact of trypanosomes on human and livestock health, trypanosomes in wildlife, although ubiquitous, have largely been considered to be non-pathogenic. We describe the genetic diversity, tissue tropism and potential pathogenicity of trypanosomes naturally infecting Western Australian marsupials. Blood samples collected from 554 live-animals and 250 tissue samples extracted from 50 carcasses of sick-euthanized or road-killed animals, belonging to 10 species of marsupials, were screened for the presence of trypanosomes using a PCR of the 18S rDNA gene. PCR results revealed a rate of infection of 67% in blood and 60% in tissues. Inferred phylogenetic trees using 18S rDNA and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) sequences showed the presence of eight genotypes that clustered into three clades: a clade including Trypanosoma copemani, a new clade closely related to Trypanosoma gilletti, and a clade including Trypanosoma H25 from an Australian kangaroo. Trypanosome infections were compared in a declining and in a stable population of the endangered Australian marsupial, the brush tailed bettong or woylie (Bettongia penicillata). This marsupial showed high rates of infection with Clade A genotypes (96%) in the declining population, whereas in the stable population, Clade B genotypes were predominant (89%). Mixed infections were common in woylies from the declining but not from the stable population. Histopathological findings associated with either mixed or single infections involving Clade A genotypes, showed a strong inflammatory process and tissue degeneration predominantly in heart, oesophagus and tongue. Trypanosomes were successfully grown in culture and for the first time we demonstrate that a genotype within Clade A has the capacity to not only colonize different tissues in the host but also to invade cells in vitro. These results provide evidence for the potential role of trypanosomes in the decline of a formerly abundant marsupial that is now critically endangered. PMID:24533319

Declining Orangutan Encounter Rates from Wallace to the Present Suggest the Species Was Once More Abundant

PubMed Central

Meijaard, Erik; Welsh, Alan; Ancrenaz, Marc; Wich, Serge; Nijman, Vincent; Marshall, Andrew J.

2010-01-01

Background Bornean orangutans (Pongo pygmaeus) currently occur at low densities and seeing a wild one is a rare event. Compared to present low encounter rates of orangutans, it is striking how many orangutan each day historic collectors like Alfred Russel Wallace were able to shoot continuously over weeks or even months. Does that indicate that some 150 years ago encounter rates with orangutans, or their densities, were higher than now? Methodology/Principal Findings We test this hypothesis by quantifying encounter rates obtained from hunting accounts, museum collections, and recent field studies, and analysing whether there is a declining trend over time. Logistic regression analyses of our data support such a decline on Borneo between the mid-19th century and the present. Even when controlled for variation in the size of survey and hunting teams and the durations of expeditions, mean daily encounter rates appear to have declined about 6-fold in areas with little or no forest disturbance. Conclusions/Significance This finding has potential consequences for our understanding of orangutans, because it suggests that Bornean orangutans once occurred at higher densities. We explore potential explanations—habitat loss and degradation, hunting, and disease—and conclude that hunting fits the observed patterns best. This suggests that hunting has been underestimated as a key causal factor of orangutan density and distribution, and that species population declines have been more severe than previously estimated based on habitat loss only. Our findings may require us to rethink the biology of orangutans, with much of our ecological understanding possibly being based on field studies of animals living at lower densities than they did historically. Our approach of quantifying species encounter rates from historic data demonstrates that this method can yield valuable information about the ecology and population density of species in the past, providing new insight into species' conservation needs. PMID:20711451

AMPK agonist AICAR delays the initial decline in lifetime-apex V̇o2 peak, while voluntary wheel running fails to delay its initial decline in female rats.

PubMed

Toedebusch, Ryan G; Ruegsegger, Gregory N; Braselton, Joshua F; Heese, Alexander J; Hofheins, John C; Childs, Tom E; Thyfault, John P; Booth, Frank W

2016-02-01

There has never been an outcome measure for human health more important than peak oxygen consumption (V̇o2 peak), yet little is known regarding the molecular triggers for its lifetime decline with aging. We examined the ability of physical activity or 5 wk of 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) administration to delay the initial aging-induced decline in lifetime-apex V̇o2 peak and potential underlying molecular mechanisms. Experiment 1 consisted of female rats with (RUN) and without (NO RUN) running wheels, while experiment 2 consisted of female nonrunning rats getting the AMPK agonist AICAR (0.5 mg/g/day) subcutaneously for 5 wk beginning at 17 wk of age. All rats underwent frequent, weekly or biweekly V̇o2 peak tests beginning at 10 wk of age. In experiment 1, lifetime-apex V̇o2 peak occurred at 19 wk of age in both RUN and NO RUN and decreased thereafter. V̇o2 peak measured across experiment 1 was ∼25% higher in RUN than in NO RUN. In experiment 2, AICAR delayed the chronological age observed in experiment 1 by 1 wk, from 19 wk to 20 wk of age. RUN and NO RUN showed different skeletal muscle transcriptomic profiles both pre- and postapex. Additionally, growth and development pathways are differentially regulated between RUN and NO RUN. Angiomotin mRNA was downregulated postapex in RUN and NO RUN. Furthermore, strong significant correlations to V̇o2 peak and trends for decreased protein concentration supports angiomotin's potential importance in our model. Contrary to our primary hypothesis, wheel running was not sufficient to delay the chronological age of lifetime-apex V̇o2 peak decline, whereas AICAR delayed it 1 wk. Copyright © 2016 the American Physiological Society.

Effects of age on a real-world What-Where-When memory task

PubMed Central

Mazurek, Adèle; Bhoopathy, Raja Meenakshi; Read, Jenny C. A.; Gallagher, Peter; Smulders, Tom V.

2015-01-01

Many cognitive abilities decline with aging, making it difficult to detect pathological changes against a background of natural changes in cognition. Most of the tests to assess cognitive decline are artificial tasks that have little resemblance to the problems faced by people in everyday life. This means both that people may have little practice doing such tasks (potentially contributing to the decline in performance) and that the tasks may not be good predictors of real-world cognitive problems. In this study, we test the performance of young people (18–25 years) and older people (60+-year-olds) on a novel, more ecologically valid test of episodic memory: the real-world What-Where-When (WWW) memory test. We also compare them on a battery of other cognitive tests, including working memory, psychomotor speed, executive function, and episodic memory. Older people show the expected age-related declines on the test battery. In the WWW memory task, older people were more likely to fail to remember any WWW combination than younger people were, although they did not significantly differ in their overall WWW score due to some older people performing as well as or better than most younger people. WWW memory performance was significantly predicted by other measures of episodic memory, such as the single-trial learning and long-term retention in the Rey Auditory Verbal Learning task and Combined Object Location Memory in the Object Relocation task. Self-reported memory complaints also predicted performance on the WWW task. These findings confirm that our real-world WWW memory task is a valid measure of episodic memory, with high ecological validity, which may be useful as a predictor of everyday memory abilities. The task will require a bit more development to improve its sensitivity to cognitive declines in aging and to potentially distinguish between mentally healthy older adults and those with early signs of cognitive pathologies. PMID:26042030

Clinically important FEV1 declines among coal miners: an exploration of previously unrecognised determinants

PubMed Central

Wang, M. L.; Petsonk, E. L.; Beeckman, L. A.; Wagner, G. R.

1999-01-01

OBJECTIVES: The relation between occupational exposure to dust and loss of ventilatory lung function is now well established. However, many exposures during work and other activities might also have important roles in determining clinically important losses of lung function. In this study, we attempted to explore additional plausible determinants of exposures and other potential risk factors for clinically important decline in forced expiratory volume in 1 second (FEV1) during work in dusty trades. METHODS: The study was performed in 264 underground coal miners whose lung function had been followed up for an average of 11 years. With an extensive follow up questionnaire, miners were asked about their occupational and non-occupational exposures, smoking, personal and family medical history, and living conditions during childhood. RESULTS: Several variables of the mine environment (as well as previously recognised effects of mining work and region) were found to be associated with excess decline in FEV1, including work in roof bolting, exposure to explosive blasting, and to control dust spraying water that had been stored in holding tanks. Use of respiratory protection seemed to reduce the risk of decline in FEV1. Other factors that were found to be associated with declines in pulmonary function included smoking, body mass, weight gain, childhood pneumonia, and childhood exposure in the home to passive tobacco smoke and possibly smoke due to wood and coal fuels. Miners with excessive decline in FEV1 were less likely to be working in mining jobs at follow up. CONCLUSIONS: These findings suggest the existence of additional risk factors for decline in lung function in dusty trades, and may be useful in developing additional approaches to the prevention of chronic respiratory disease.   PMID:10658541

Ancient and Contemporary DNA Reveal a Pre-Human Decline but No Population Bottleneck Associated with Recent Human Persecution in the Kea (Nestor notabilis)

PubMed Central

Dussex, Nicolas; Rawlence, Nicolas J.; Robertson, Bruce C.

2015-01-01

The impact of population bottlenecks is an important factor to consider when assessing species survival. Population declines can considerably limit the evolutionary potential of species and make them more susceptible to stochastic events. New Zealand has a well documented history of decline of endemic avifauna related to human colonization. Here, we investigate the genetic effects of a recent population decline in the endangered kea (Nestor notabilis). Kea have undergone a long-lasting persecution between the late 1800s to 1970s where an estimated 150,000 kea were culled under a governmental bounty scheme. Kea now number 1,000–5,000 individuals in the wild and it is likely that the recent population decline may have reduced the genetic diversity of the species. Comparison of contemporary (n = 410), historical (n = 15) and fossil samples (n = 4) showed a loss of mitochondrial diversity since the end of the last glaciation (Otiran Glacial) but no loss of overall genetic diversity associated with the cull. Microsatellite data indicated a recent bottleneck for only one population and a range-wide decline in Ne dating back some 300 – 6,000 years ago, a period predating European arrival in NZ. These results suggest that despite a recent human persecution, kea might have experienced a large population decline before stabilizing in numbers prior to human settlement of New Zealand in response to Holocene changes in habitat distribution. Our study therefore highlights the need to understand the respective effects of climate change and human activities on endangered species dynamics when proposing conservation guidelines. PMID:25719752

Heterogeneity in Rate of Decline in Grip, Hip, and Knee Strength and the Risk of All-Cause Mortality: The Women’s Health and Aging Study II

PubMed Central

Xue, Qian-Li; Beamer, Brock A.; Chaves, Paulo H.M.; Guralnik, Jack M.; Fried, Linda P.

2010-01-01

OBJECTIVES To assess the relationship between rate of change in muscle strength and all-cause mortality. DESIGN A prospective observational study of the causes and course of physical disability. SETTING Twelve contiguous ZIP code areas in Baltimore, Maryland. PARTICIPANTS Three hundred and seven community-dwelling women aged 70–79 years at study baseline. MEASUREMENTS The outcome is all-cause mortality (1994–2009); predictors include up to seven repeated measurements of handgrip, knee extension, and hip flexion strength, with a median follow-up time of 9 years. Demographic factors, body mass index, smoking status, number of chronic diseases, depressive symptoms, physical activity, Interlukin-6, and albumin were assessed at baseline and included as confounders. The associations between declining muscle strength and mortality were assessed using a joint longitudinal and survival model.. RESULTS Grip and hip strength declined an average of 1.10 and 1.31 kg per year between age 70 and 75and 0.50 and 0.39 kg/year thereafter, respectively; knee strength declined at a constant rate of 0.57 kg/year. Faster rates of decline in grip and hip strength, but not knee strength, independently predicted of mortality after accounting for their baseline levels and potential confounders (Hazard Ratio (HR)=1.33 (95% confidence interval (CI)=1.06–1.67), 1.14 (CI=0.91–1.41), and 2.62 (CI=1.43–4.78) for every 0.5 standard deviation increase in rate of decline in grip, knee, and hip strength, respectively. CONCLUSION Monitoring the rate of decline in grip and hip flexion strength in addition to the absolute levels may greatly improve the identification of women most at risk of dying. PMID:21054287

Perceived Consequences of Risky Behaviors: Adults and Adolescents.

ERIC Educational Resources Information Center

Beyth-Marom, Ruth; And Others

1993-01-01

Adults and adolescents listed possible consequences of either accepting or declining opportunities to engage in various potentially risky behaviors, such as drinking and driving, and skipping school. Response patterns were similar for both groups. (MM)

Morphological Correlates of Hearing Loss after Cochlear Implantation and Electro-Acoustic Stimulation in a Hearing-Impaired Guinea Pig Model

PubMed Central

Reiss, Lina A.J.; Stark, Gemaine; Nguyen-Huynh, Anh T.; Spear, Kayce A.; Zhang, Hongzheng; Tanaka, Chiemi; Li, Hongzhe

2016-01-01

Hybrid or electro-acoustic stimulation (EAS) cochlear implants (CIs) are designed to provide high-frequency electric hearing together with residual low-frequency acoustic hearing. However, 30-50% of EAS CI recipients lose residual hearing after implantation. The objective of this study was to determine the mechanisms of EAS-induced hearing loss in an animal model with high-frequency hearing loss. Guinea pigs were exposed to 24 hours of noise (12-24 kHz at 116 dB) to induce a high-frequency hearing loss. After recovery, two groups of animals were implanted (n=6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no stimulation during this time frame. A third group (n=6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem responses were recorded biweekly to monitor changes in hearing. The organ of Corti was immunolabeled with phalloidin, anti-CtBP2, and anti-GluR2 to quantify hair cells, ribbons and post-synaptic receptors. The lateral wall was immunolabeled with phalloidin and lectin to quantify stria vascularis capillary diameters. Bimodal or trimodal diameter distributions were observed; the number and location of peaks were objectively determined using the Aikake Information Criterion and Expectation Maximization algorithm. Noise exposure led to immediate hearing loss at 16-32 kHz for all groups. Cochlear implantation led to additional hearing loss at 4-8 kHz; this hearing loss was negatively and positively correlated with minimum and maximum peaks of the bimodal or trimodal distributions of stria vascularis capillary diameters, respectively. After chronic stimulation, no significant group changes in thresholds were seen; however, elevated thresholds at 1 kHz in implanted, stimulated animals were significantly correlated with decreased presynaptic ribbon and postsynaptic receptor counts. Inner and outer hair cell counts did not differ between groups and were not correlated with threshold shifts at any frequency. As in the previous study in a normal-hearing model, stria vascularis capillary changes were associated with immediate hearing loss after implantation, while little to no hair cell loss was observed even in cochlear regions with threshold shifts as large as 40-50 dB. These findings again support a role of lateral wall blood flow changes, rather than hair cell loss, in hearing loss after surgical trauma, and implicate the endocochlear potential as a factor in implantation-induced hearing loss. Further, the analysis of the hair cell ribbons and post-synaptic receptors suggest that delayed hearing loss may be linked to synapse or peripheral nerve loss due to stimulation excitotoxicity or inflammation. Further research is needed to separate these potential mechanisms of delayed hearing loss. PMID:26087114

Chronic groundwater decline: A multi-decadal analysis of groundwater trends under extreme climate cycles

NASA Astrophysics Data System (ADS)

Le Brocque, Andrew F.; Kath, Jarrod; Reardon-Smith, Kathryn

2018-06-01

Chronic groundwater decline is a concern in many of the world's major agricultural areas. However, a general lack of accurate long-term in situ measurement of groundwater depth and analysis of trends prevents understanding of the dynamics of these systems at landscape scales. This is particularly worrying in the context of future climate uncertainties. This study examines long-term groundwater responses to climate variability in a major agricultural production landscape in southern Queensland, Australia. Based on records for 381 groundwater bores, we used a modified Mann-Kendall non-parametric test and Sen's slope estimator to determine groundwater trends across a 26-year period (1989-2015) and in distinct wet and dry climatic phases. Comparison of trends between climatic phases showed groundwater level recovery during wet phases was insufficient to offset the decline in groundwater level from the previous dry phase. Across the entire 26-year sampling period, groundwater bore levels (all bores) showed an overall significant declining trend (p < 0.05) of an average 0.06 m year-1. Fifty-one bores (20%) exhibited significant declining groundwater levels (p < 0.05), 25 bores (10%) exhibited significant rising groundwater levels (p < 0.05), and 175 bores (70%) exhibited no significant change in groundwater levels (p > 0.05). Spatially, both declining and rising bores were highly clustered. We conclude that over 1989-2015 there is a significant net decline in groundwater levels driven by a smaller subset of highly responsive bores in high irrigation areas within the catchment. Despite a number of targeted policy interventions, chronic groundwater decline remains evident in the catchment. We argue that this is likely to continue and to occur more widely under potential climate change and that policy makers, groundwater users and managers need to engage in planning to ensure the sustainability of this vital resource.

Cognitive Decline Is Associated with Risk Aversion and Temporal Discounting in Older Adults without Dementia

PubMed Central

James, Bryan D.; Boyle, Patricia A.; Yu, Lei; Han, S. Duke; Bennett, David A.

2015-01-01

Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that subtle age-related changes in cognition can detrimentally affect individual preferences that are critical for maintaining health and well being. PMID:25838074

Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

PubMed

James, Bryan D; Boyle, Patricia A; Yu, Lei; Han, S Duke; Bennett, David A

2015-01-01

Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that subtle age-related changes in cognition can detrimentally affect individual preferences that are critical for maintaining health and well being.

Cognitive function trajectories and their determinants in older people: 8 years of follow-up in the English Longitudinal Study of Ageing.

PubMed

Zaninotto, Paola; Batty, G David; Allerhand, Michael; Deary, Ian J

2018-04-24

Maintaining cognitive function is an important aspect of healthy ageing. In this study, we examined age trajectories of cognitive decline in a large nationally representative sample of older people in England. We explored the factors that influence such decline and whether these differed by gender. Latent growth curve modelling was used to explore age-specific changes, and influences on them, in an 8-year period in memory, executive function, processing speed and global cognitive function among 10 626 participants in the English Longitudinal Study of Ageing. We run gender-specific models with the following exposures: age, education, wealth, childhood socioeconomic status, cardiovascular disease, diabetes, physical function, body mass index, physical activity, alcohol, smoking, depression and dementia. After adjustment, women had significantly less decline than men in memory (0.011, SE 0.006), executive function (0.012, SE 0.006) and global cognitive function (0.016, SE 0.004). Increasing age and dementia predicted faster rates of decline in all cognitive function domains. Depression and alcohol consumption predicted decline in some cognitive function domains in men only. Poor physical function, physical inactivity and smoking were associated with faster rates of decline in specific cognitive domains in both men and women. For example, relative to study members who were physically active, the sedentary experienced greater declines in memory (women -0.018, SE 0.009) and global cognitive function (men -0.015, SE 0.007 and women -0.016, SE 0.007). The potential determinants of cognitive decline identified in this study, in particular modifiable risk factors, should be tested in the context of randomised controlled trials. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Is the Mediterranean diet a feasible approach to preserving cognitive function and reducing risk of dementia for older adults in Western countries? New insights and future directions.

PubMed

Knight, Alissa; Bryan, Janet; Murphy, Karen

2016-01-01

The rise in the ageing population has resulted in increased incident rates of cognitive impairment and dementia. The subsequent financial and societal burden placed on an already strained public health care system is of increasing concern. Evidence from recent studies has revealed modification of lifestyle and dietary behaviours is, at present, the best means of prevention. Some of the most important findings, in relation to the Mediterranean diet (MedDiet) and the contemporary Western diet, and potential molecular mechanisms underlying the effects of these two diets on age-related cognitive function, are discussed in this review. A major aim of this review was to discuss whether or not a MedDiet intervention would be a feasible preventative approach against cognitive decline for older adults living in Western countries. Critical appraisal of the literature does somewhat support this idea. Demonstrated evidence highlights the MedDiet as a potential strategy to reduce cognitive decline in older age, and suggests the Western diet may play a role in the aetiology of cognitive decline. However, strong intrinsic Western socio-cultural values, traditions and norms may impede on the feasibility of this notion. Copyright © 2015 Elsevier B.V. All rights reserved.

Modulation of GH/IGF-1 axis: potential strategies to counteract sarcopenia in older adults.

PubMed

Giovannini, Silvia; Marzetti, Emanuele; Borst, Stephen E; Leeuwenburgh, Christiaan

2008-10-01

Aging is associated with progressive decline of skeletal muscle mass and function. This condition, termed sarcopenia, is associated with several adverse outcomes, including loss of autonomy and mortality. Due to the high prevalence of sarcopenia, a deeper understanding of its pathophysiology and possible remedies represents a high public health priority. Evidence suggests the existence of a relationship between declining growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels and age-related changes in body composition and physical function. Therefore, the age-dependent decline of GH and IGF-1 serum levels may promote frailty by contributing to the loss of muscle mass and strength. Preclinical studies showed that infusion of angiotensin II produced a marked reduction in body weight, accompanied by decreased serum and muscle levels of IGF-1. Conversely, overexpression of muscle-specific isoform of IGF-1 mitigates angiotensin II-induced muscle loss. Moreover, IGF-1 serum levels have been shown to increase following angiotensin converting enzyme inhibitors (ACEIs) treatment. Here we will review the most recent evidence regarding age-related changes of the GH/IGF-1 axis and its modulation by several interventions, including ACEIs which might represent a potential novel strategy to delay the onset and impede the progression of sarcopenia.

Energy efficiency standards and innovation

NASA Astrophysics Data System (ADS)

Morrison, Geoff

2015-01-01

Van Buskirk et al (2014 Environ. Res. Lett. 9 114010) demonstrate that the purchase price, lifecycle cost and price of improving efficiency (i.e. the incremental price of efficiency gain) decline at an accelerated rate following the adoption of the first energy efficiency standards for five consumer products. The authors show these trends using an experience curve framework (i.e. price/cost versus cumulative production). While the paper does not draw a causal link between standards and declining prices, they provide suggestive evidence using markets in the US and Europe. Below, I discuss the potential implications of the work.

CORAL REEF BIOCRITERIA

EPA Science Inventory

Coral reefs worldwide are experiencing the greatest decline of their known existence and few tools are available to offset the growing impacts of human coastal and watershed activities. Biocriteria are a potentially effective means to evaluate and restore impaired waters, but are...

Conservation genetics of the fisher (Martes pennanti) based on mitochondrial DNA sequencing

Treesearch

R.E. Drew; J.G. Hallett; K.B. Aubry; K.W. Cullings; S.M Koepf; W.J. Zielinski

2003-01-01

Translocation of animals to re-establish extirpated populations or to maintain declining ones has often been carried out without genetic information on source or target opulations, or adequate consideration of the potential...

MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS

EPA Science Inventory

Understanding the consequences of the declining global cover of mangroves due to anthropogenic disturbance necessitates consideration of how mangrove-derived nutrients contribute to threatened coral reef systems. We sampled potential sources of organic matter and a suite of sessi...

A perspective on modern pesticides, pelagic fish declines, and unknown ecological resilience in highly managed ecosystems

USGS Publications Warehouse

Scholz, Nathaniel L.; Fleishman, Erica; Brown, Larry; Werner, Inge; Johnson, Michael L.; Brooks, Marjorie L.; Mitchelmore, Carys L.; Schlenk, Daniel

2012-01-01

Pesticides applied on land are commonly transported by runoff or spray drift to aquatic ecosystems, where they are potentially toxic to fishes and other nontarget organisms. Pesticides add to and interact with other stressors of ecosystem processes, including surface-water diversions, losses of spawning and rearing habitats, nonnative species, and harmful algal blooms. Assessing the cumulative effects of pesticides on species or ecological functions has been difficult for historical, legal, conceptual, and practical reasons. To explore these challenges, we examine current-use (modern) pesticides and their potential connections to the abundances of fishes in the San Francisco Estuary (California). Declines in delta smelt (Hypomesus transpacificus), Chinook salmon (Oncorhynchus tshawytscha), and other species have triggered mandatory and expensive management actions in the urbanizing estuary and agriculturally productive Central Valley. Our inferences are transferable to other situations in which toxics may drive changes in ecological status and trends.

IGF-1, the cross road of the nutritional, inflammatory and hormonal pathways to frailty.

PubMed

Maggio, Marcello; De Vita, Francesca; Lauretani, Fulvio; Buttò, Valeria; Bondi, Giuliana; Cattabiani, Chiara; Nouvenne, Antonio; Meschi, Tiziana; Dall'Aglio, Elisabetta; Ceda, Gian Paolo

2013-10-21

The decline in functional capacity is a heterogeneous phenomenon in the elderly. An accelerated ageing determines a frail status. It results in an increased vulnerability to stressors for decreased physiological reserves. The early identification of a frail status is essential for preventing loss of functional capacity, and its clinical consequences. Frailty and mobility limitation result from an interplay of different pathways including multiple anabolic deficiency, inflammation, oxidative stress, and a poor nutritional status. However, the age-related decline in insulin-like growth factor 1 (IGF-1) bioactivity deserves special attention as it could represent the ideal crossroad of endocrine, inflammatory, and nutritional pathways to frailty. Several minerals, namely magnesium, selenium, and zinc, appear to be important determinants of IGF-1 bioactivity. This review aims to provide an overview of the potential usefulness of nutrients modulating IGF-1 as potential therapeutic targets in the prevention of mobility limitation occurring in frail older subjects.

The Potential Impact of an Anthrax Attack on Real Estate Prices and Foreclosures in Seattle.

PubMed

Dormady, Noah; Szelazek, Thomas; Rose, Adam

2014-01-01

This article provides a methodology for the economic analysis of the potential consequences of a simulated anthrax terrorism attack on real estate within the Seattle metropolitan area. We estimate spatially disaggregated impacts on median sales price of residential housing within the Seattle metro area following an attack on the central business district (CBD). Using a combination of longitudinal panel regression and GIS analysis, we find that the median sales price in the CBD could decline by as much as $280,000, and by nearly $100,000 in nearby communities. These results indicate that total residential property values could decrease by over $50 billion for Seattle, or a 33% overall decline. We combine these estimates with HUD's 2009 American Housing Survey (AHS) to further predict 70,000 foreclosures in Seattle spatial zones following the terrorism event. © 2013 Society for Risk Analysis.

A spatial analysis of population dynamics and climate change in Africa: potential vulnerability hot spots emerge where precipitation declines and demographic pressures coincide

USGS Publications Warehouse

López-Carr, David; Pricope, Narcisa G.; Aukema, Juliann E.; Jankowska, Marta M.; Funk, Christopher C.; Husak, Gregory J.; Michaelsen, Joel C.

2014-01-01

We present an integrative measure of exposure and sensitivity components of vulnerability to climatic and demographic change for the African continent in order to identify “hot spots” of high potential population vulnerability. Getis-Ord Gi* spatial clustering analyses reveal statistically significant locations of spatio-temporal precipitation decline coinciding with high population density and increase. Statistically significant areas are evident, particularly across central, southern, and eastern Africa. The highly populated Lake Victoria basin emerges as a particularly salient hot spot. People located in the regions highlighted in this analysis suffer exceptionally high exposure to negative climate change impacts (as populations increase on lands with decreasing rainfall). Results may help inform further hot spot mapping and related research on demographic vulnerabilities to climate change. Results may also inform more suitable geographical targeting of policy interventions across the continent.

Direct and indirect effects of climate change on amphibian populations

USGS Publications Warehouse

Blaustein, Andrew R.; Walls, Susan C.; Bancroft, Betsy A.; Lawler, Joshua J.; Searle, Catherine L.; Gervasi, Stephanie S.

2010-01-01

As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

Solar on the Rise: How Cost Declines and Grid Integration Shape Solar's Growth Potential in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J; Denholm, Paul L; Feldman, David J

During the past decade, solar power has experienced transformative price declines, enabling it to become a viable electricity source that is supplying 1% of U.S. and world electricity. Further cost reductions are expected to enable substantially greater solar deployment, and new Department of Energy cost targets for utility-scale photovoltaics (PV) and concentrating solar thermal power are $0.03/kW h and $0.05/kW h by 2030, respectively. However, cost reductions are no longer the only significant challenge for PV - addressing grid integration challenges and increasing grid flexibility are critical as the penetration of PV electricity on the grid increases. The development ofmore » low cost energy storage is particularly synergistic with low cost PV, as cost declines in each technology are expected to support greater market opportunities for the other.« less

Declining resilience of ecosystem functions under biodiversity loss.

PubMed

Oliver, Tom H; Isaac, Nick J B; August, Tom A; Woodcock, Ben A; Roy, David B; Bullock, James M

2015-12-08

The composition of species communities is changing rapidly through drivers such as habitat loss and climate change, with potentially serious consequences for the resilience of ecosystem functions on which humans depend. To assess such changes in resilience, we analyse trends in the frequency of species in Great Britain that provide key ecosystem functions--specifically decomposition, carbon sequestration, pollination, pest control and cultural values. For 4,424 species over four decades, there have been significant net declines among animal species that provide pollination, pest control and cultural values. Groups providing decomposition and carbon sequestration remain relatively stable, as fewer species are in decline and these are offset by large numbers of new arrivals into Great Britain. While there is general concern about degradation of a wide range of ecosystem functions, our results suggest actions should focus on particular functions for which there is evidence of substantial erosion of their resilience.

Evidence for age-associated cognitive decline from Internet game scores.

PubMed

Geyer, Jason; Insel, Philip; Farzin, Faraz; Sternberg, Daniel; Hardy, Joseph L; Scanlon, Michael; Mungas, Dan; Kramer, Joel; Mackin, R Scott; Weiner, Michael W

2015-06-01

Lumosity's Memory Match (LMM) is an online game requiring visual working memory. Change in LMM scores may be associated with individual differences in age-related changes in working memory. Effects of age and time on LMM learning and forgetting rates were estimated using data from 1890 game sessions for users aged 40 to 79 years. There were significant effects of age on baseline LMM scores (β = -.31, standard error or SE = .02, P < .0001) and lower learning rates (β = -.0066, SE = .0008, P < .0001). A sample size of 202 subjects/arm was estimated for a 1-year study for subjects in the lower quartile of game performance. Online memory games have the potential to identify age-related decline in cognition and to identify subjects at risk for cognitive decline with smaller sample sizes and lower cost than traditional recruitment methods.

Sensitivity of commercial pumpkin yield to potential decline among different groups of pollinating bees.

PubMed

Pfister, Sonja C; Eckerter, Philipp W; Schirmel, Jens; Cresswell, James E; Entling, Martin H

2017-05-01

The yield of animal-pollinated crops is threatened by bee declines, but its precise sensitivity is poorly known. We therefore determined the yield dependence of Hokkaido pumpkin in Germany on insect pollination by quantifying: (i) the relationship between pollen receipt and fruit set and (ii) the cumulative pollen deposition of each pollinator group. We found that approximately 2500 pollen grains per flower were needed to maximize fruit set. At the measured rates of flower visitation, we estimated that bumblebees (21 visits/flower lifetime, 864 grains/visit) or honeybees (123 visits, 260 grains) could individually achieve maximum crop yield, whereas halictid bees are ineffective (11 visits, 16 grains). The pollinator fauna was capable of delivering 20 times the necessary amount of pollen. We therefore estimate that pumpkin yield was not pollination-limited in our study region and that it is currently fairly resilient to single declines of honeybees or wild bumblebees.

The influence of vitamins E and C and exercise on brain aging.

PubMed

Mock, J Thomas; Chaudhari, Kiran; Sidhu, Akram; Sumien, Nathalie

2017-08-01

Age-related declines in motor and cognitive function have been associated with increases in oxidative stress. Accordingly, interventions capable of reducing the oxidative burden would be capable of preventing or reducing functional declines occurring during aging. Popular interventions such as antioxidant intake and moderate exercise are often recommended to attain healthy aging and have the capacity to alter redox burden. This review is intended to summarize the outcomes of antioxidant supplementation (more specifically of vitamins C and E) and exercise training on motor and cognitive declines during aging, and on measures of oxidative stress. Additionally, we will address whether co-implementation of these two types of interventions can potentially further their individual benefits. Together, these studies highlight the importance of using translationally-relevant parameters for interventions and to study their combined outcomes on healthy brain aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Identifying species conservation strategies to reduce disease-associated declines

USGS Publications Warehouse

Gerber, Brian D.; Converse, Sarah J.; Muths, Erin L.; Crockett, Harry J.; Mosher, Brittany A.; Bailey, Larissa L.

2018-01-01

Emerging infectious diseases (EIDs) are a salient threat to many animal taxa, causing local and global extinctions, altering communities and ecosystem function. The EID chytridiomycosis is a prominent driver of amphibian declines, which is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). To guide conservation policy, we developed a predictive decision-analytic model that combines empirical knowledge of host-pathogen metapopulation dynamics with expert judgment regarding effects of management actions, to select from potential conservation strategies. We apply our approach to a boreal toad (Anaxyrus boreas boreas) and Bd system, identifying optimal strategies that balance tradeoffs in maximizing toad population persistence and landscape-level distribution, while considering costs. The most robust strategy is expected to reduce the decline of toad breeding sites from 53% to 21% over 50 years. Our findings are incorporated into management policy to guide conservation planning. Our online modeling application provides a template for managers of other systems challenged by EIDs.

Fertility Decline, Gender Composition of Families, and Expectations of Old Age Support.

PubMed

Allendorf, Keera

2015-08-01

Recent fertility declines in non-Western countries may have the potential to transform gender systems. One pathway for such transformations is the creation of substantial proportions of families with children of only one gender. Such families, particularly those with only daughters, may facilitate greater symmetry between sons and daughters. This article explores whether such shifts may influence gendered expectations of old age support. In keeping with patriarchal family systems, old age support is customarily provided by sons, but not daughters, in India. Using data from the 2005 Indian Human Development Survey, I find that women with sons overwhelmingly expect old age support from a son. By contrast, women with only daughters largely expect support from a daughter or a source besides a child. These findings suggest that fertility decline may place demographic pressure on gendered patterns of old age support and the gender system more broadly.

Fertility Decline, Gender Composition of Families, and Expectations of Old Age Support

PubMed Central

Allendorf, Keera

2017-01-01

Recent fertility declines in non-Western countries may have the potential to transform gender systems. One pathway for such transformations is the creation of substantial proportions of families with children of only one gender. Such families, particularly those with only daughters, may facilitate greater symmetry between sons and daughters. This article explores whether such shifts may influence gendered expectations of old age support. In keeping with patriarchal family systems, old age support is customarily provided by sons, but not daughters, in India. Using data from the 2005 Indian Human Development Survey, I find that women with sons overwhelmingly expect old age support from a son. By contrast, women with only daughters largely expect support from a daughter or a source besides a child. These findings suggest that fertility decline may place demographic pressure on gendered patterns of old age support and the gender system more broadly. PMID:28344373

Evaluating red-cockaded woodpeckers for exposure to West Nile Virus and blood parasites

USGS Publications Warehouse

Dusek, Robert J.; Richardson, D.; Egstad, Kristina F.; Heisey, Dennis M.

2006-01-01

A marked decline in the Picoides borealis (Red-cockaded Woodpecker [RCW]) population at Noxubee National Wildlife Refuge, MS, was observed in 2002. Demographic changes - including absence of hatch-year birds, decreases in size of known groups, and loss of known groups-were identified during annual fall surveys and are uncharacteristic of RCW populations. In 2003, a serosurvey of 28 adult RCWs was conducted to investigate the presence of West Nile virus (WNV) exposure in the population, possibly providing insight into whether WNV may have been responsible for this decline. Blood smears were also examined from these birds for blood parasites. We found no evidence of West Nile virus exposure or blood parasites in any of the RCWs sampled. Further monitoring of the RCW population and WNV activity in other species at Noxubee NWR is recommended to further evaluate the potential role of WNV and blood parasites in their decline.

The decline of Arab oil revenues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farid, A.M.

1986-01-01

Since 1981, Arab oil revenues have declined by about 40-50%. This has had an enormous impact on the Arab economies as well as on economic and political relations between the Arab world, the industrialised world and the Third world. This book reviews how lower oil revenues have affected Arab countries and the international economy. It also considers the future prospects for Arab oil and the world oil industry. It analyses the various assessment of the life span of oil, the forecasts concerning the development of alternative sources of energy and the factors governing the demand for oil. Although the outlookmore » for the Arab economies appears gloomy in many respects, the book argues that there is potential within the Arab world to overcome the decline in oil revenues. However it will require great efforts in political and economic co-operation amongst Arab states.« less

Sensitivity of commercial pumpkin yield to potential decline among different groups of pollinating bees

PubMed Central

Eckerter, Philipp W.; Schirmel, Jens; Cresswell, James E.; Entling, Martin H.

2017-01-01

The yield of animal-pollinated crops is threatened by bee declines, but its precise sensitivity is poorly known. We therefore determined the yield dependence of Hokkaido pumpkin in Germany on insect pollination by quantifying: (i) the relationship between pollen receipt and fruit set and (ii) the cumulative pollen deposition of each pollinator group. We found that approximately 2500 pollen grains per flower were needed to maximize fruit set. At the measured rates of flower visitation, we estimated that bumblebees (21 visits/flower lifetime, 864 grains/visit) or honeybees (123 visits, 260 grains) could individually achieve maximum crop yield, whereas halictid bees are ineffective (11 visits, 16 grains). The pollinator fauna was capable of delivering 20 times the necessary amount of pollen. We therefore estimate that pumpkin yield was not pollination-limited in our study region and that it is currently fairly resilient to single declines of honeybees or wild bumblebees. PMID:28573019

Changing Seasonality of Tundra Vegetation and Associated Climatic Variables

NASA Astrophysics Data System (ADS)

Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Bieniek, P.; Epstein, H. E.; Comiso, J. C.; Pinzon, J.; Tucker, C. J.; Steele, M.; Ermold, W. S.; Zhang, J.

2014-12-01

This study documents changes in the seasonality of tundra vegetation productivity and its associated climate variables using long-term data sets. An overall increase of Pan-Arctic tundra greenness potential corresponds to increased land surface temperatures and declining sea ice concentrations. While sea ice has continued to decline, summer land surface temperature and vegetation productivity increases have stalled during the last decade in parts of the Arctic. To understand the processes behind these features we investigate additional climate parameters. This study employs remotely sensed weekly 25-km sea ice concentration, weekly surface temperature, and bi-weekly NDVI from 1982 to 2013. Maximum NDVI (MaxNDVI, Maximum Normalized Difference Vegetation Index), Time Integrated NDVI (TI-NDVI), Summer Warmth Index (SWI, sum of degree months above freezing during May-August), ocean heat content (PIOMAS, model incorporating ocean data assimilation), and snow water equivalent (GlobSnow, assimilated snow data set) are explored. We analyzed the data for the full period (1982-2013) and for two sub-periods (1982-1998 and 1999-2013), which were chosen based on the declining Pan-Arctic SWI since 1998. MaxNDVI has increased from 1982-2013 over most of the Arctic but has declined from 1999 to 2013 over western Eurasia, northern Canada, and southwest Alaska. TI-NDVI has trends that are similar to those for MaxNDVI for the full period but displays widespread declines over the 1999-2013 period. Therefore, as the MaxNDVI has continued to increase overall for the Arctic, TI-NDVI has been declining since 1999. SWI has large relative increases over the 1982-2013 period in eastern Canada and Greenland and strong declines in western Eurasia and southern Canadian tundra. Weekly Pan-Arctic tundra land surface temperatures warmed throughout the summer during the 1982-1998 period but display midsummer declines from 1999-2013. Weekly snow water equivalent over Arctic tundra has declined over most seasons but shows slight increases in spring in North America and during fall over Eurasia. Later spring or earlier fall snow cover can both lead to reductions in TI-NDVI. The time-varying spatial patterns of NDVI trends can be largely explained using either snow cover or land surface temperature trends.

The potential impact of white-nose syndrome on the conservation status of north american bats.

PubMed

Alves, Davi M C C; Terribile, Levi C; Brito, Daniel

2014-01-01

White-Nose syndrome (WNS) is an emergent infectious disease that has already killed around six million bats in North America and has spread over two thousand kilometers from its epicenter. However, only a few studies on the possible impacts of the fungus on bat hosts were conducted, particularly concerning its implications for bat conservation. We predicted the consequences of WNS spread by generating a map with potential areas for its occurrence based on environmental conditions in sites where the disease already occurs, and overlaid it with the geographic distribution of all hibernating bats in North America. We assumed that all intersection localities would negatively affect local bat populations and reassessed their conservation status based on their potential population decline. Our results suggest that WNS will not spread widely throughout North America, being mostly restricted to the east and southeast regions. In contrast, our most pessimistic scenario of population decline indicated that the disease would threaten 32% of the bat species. Our results could help further conservation plans to preserve bat diversity in North America.

Do Customers Flee from HIV? A Survey of HIV Stigma and Its Potential Economic Consequences on Small Businesses in Tshwane (Pretoria), South Africa*

PubMed Central

Chao, Li-Wei; Szrek, Helena; Leite, Rui; Ramlagan, Shandir; Peltzer, Karl

2016-01-01

HIV stigma and discrimination affect care-seeking behavior and may also affect entrepreneurial activity. We interview 2,382 individuals in Pretoria, South Africa, and show that respondents believe that businesses with known HIV+ workers may lose up to half of their customers, although the impact depends on the type of business. Survey respondents’ fear of getting HIV from consuming everyday products sold by the business - despite a real infection risk of zero - was a major factor driving perceived decline in customers, especially among food businesses. Respondents’ perceptions of the decline in overall life satisfaction when one gets sick from HIV and the respondent’s dislike of people with HIV were also important predictors of potential customer exit. We suggest policy mechanisms that could improve the earnings potential of HIV+ workers: reducing public health scare tactics that exacerbate irrational fear of HIV infection risk and enriching public health education about HIV and ARVs to improve perceptions about people with HIV. PMID:27385027

Hydraulic Function in Australian Tree Species during Drought-Induced Mortality

NASA Astrophysics Data System (ADS)

Tissue, D.; Maier, C.; Creek, D.; Choat, B.

2016-12-01

Drought induced tree mortality and decline are key issues facing forest ecology and management. Here, we primarily investigated the hydraulic limitations underpinning drought-induced mortality in three Australian tree species. Using field-based large rainout shelters, three angiosperm species (Casuarina cunninghamiana, Eucalyptus sideroxylon, Eucalyptus tereticornis) were subjected to two successive drought and recovery cycles, prior to a subsequent long and extreme drought to mortality; total duration of experiment was 2.5 years. Leaf gas exchange, leaf and stem hydraulics, and carbon reserves were monitored during the experiment. Trees died as a result of failure in the hydraulic transport system, primarily related to water stress induced embolism. Stomatal closure occurred prior to the induction of significant embolism in the stem xylem of all species. Nonetheless, trees suffered a rapid decline in xylem water potential and increase in embolism during the severe drought treatment. Trees died at water potentials causing greater than 90% loss of hydraulic conductivity in the stem, providing support for the theory that lethal water potential is correlated with complete loss of hydraulic function in the stem xylem of angiosperms.

Evaluating growth of the Porcupine Caribou Herd using a stochastic model

USGS Publications Warehouse

Walsh, Noreen E.; Griffith, Brad; McCabe, Thomas R.

1995-01-01

Estimates of the relative effects of demographic parameters on population rates of change, and of the level of natural variation in these parameters, are necessary to address potential effects of perturbations on populations. We used a stochastic model, based on survival and reproduction estimates of the Porcupine Caribou (Rangifer tarandus granti) Herd (PCH), during 1983-89 and 1989-92 to obtain distributions of potential population rates of change (r). The distribution of r produced by 1,000 trajectories of our simulation model (1983-89, r̄ = 0.013; 1989-92, r̄ = 0.003) encompassed the rate of increase calculated from an independent series of photo-survey data over the same years (1983-89, r = 0.048; 1989-92, r = -0.035). Changes in adult female survival had the largest effect on r, followed by changes in calf survival. We hypothesized that petroleum development on calving grounds, or changes in calving and post-calving habitats due to global climate change, would affect model input parameters. A decline in annual adult female survival from 0.871 to 0.847, or a decline in annual calf survival from 0.518 to 0.472, would be sufficient to cause a declining population, if all other input estimates remained the same. We then used these lower survival rates, in conjunction with our estimated amount of among-year variation, to determine a range of resulting population trajectories. Stochastic models can be used to better understand dynamics of populations, optimize sampling investment, and evaluate potential effects of various factors on population growth.

Soil microbial communities buffer physiological responses to drought stress in three hardwood species.

PubMed

Kannenberg, Steven A; Phillips, Richard P

2017-03-01

Trees possess myriad adaptations for coping with drought stress, but the extent to which their drought responses are influenced by interactions with soil microbes is poorly understood. To explore the role of microbes in mediating tree responses to drought stress, we exposed saplings of three species (Acer saccharum, Liriodendron tulipifera, and Quercus alba) to a four week experimental drought in mesocosms. Half of the pots were inoculated with a live soil slurry (i.e., a microbial inoculum derived from soils beneath the canopies of mature A. saccharum, L. tulipifera or Q. alba stands), while the other half of the pots received a sterile soil slurry. Soil microbes ameliorated drought stress in L. tulipifera by minimizing reductions in leaf water potential and by reducing photosynthetic declines. In A. saccharum, soil microbes reduced drought stress by lessening declines in leaf water potential, though these changes did not buffer the trees from declining photosynthetic rates. In Q. alba, soil microbes had no effects on leaf physiological parameters during drought stress. In all species, microbes had no significant effects on dynamic C allocation during drought stress, suggesting that microbial effects on plant physiology were unrelated to source-sink dynamics. Collectively, our results suggest that soil microbes have the potential to alter key parameters that are used to diagnose drought sensitivity (i.e., isohydry or anisohydry). To the extent that our results reflect dynamics occurring in forests, a revised perspective on plant hydraulic strategies that considers root-microbe interactions may lead to improved predictions of forest vulnerability to drought.

Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales

PubMed Central

Stickler, Claudia M.; Coe, Michael T.; Costa, Marcos H.; Nepstad, Daniel C.; McGrath, David G.; Dias, Livia C. P.; Rodrigues, Hermann O.; Soares-Filho, Britaldo S.

2013-01-01

Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations’ energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local “direct” effects (through changes in ET within the watershed) and the potential regional “indirect” effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world’s largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4–8% and 10–12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6–36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry’s own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests. PMID:23671098

Carbon dioxide and light responses of photosynthesis in cowpea and pigeonpea during water deficit and recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, F.B.; Setter, T.L.; McDavid, C.R.

Greenhouse-grown pigeonpea (Cajunus cajan, (L.)) and cowpea (Vigna unguiculata, (L.)) were well-watered or subjected to low water potential by withholding water to compare their modes of adaptation to water-limited conditions. Leaf CO/sub 2/ exchange rate (CER), leaf diffusive conductance to CO/sub 2/ (g/sub L/), and CO/sub 2/ concentration in the leaf intercellular air space (C/sub i/) were determined at various CO/sub 2/ concentrations and photon flux densities (PFD) of photosynthetically active radiation. In cowpea, g/sub L/ declined to less than 15% of controls and total water potential (Psi/sub w/) at midafternoon declined to -0.8 megapascal after 5 days of withholdingmore » water, whereas g/sub L/ in pigeonpea was about 40% of controls even though midafternoon Psi/sub w/ was -1.9 megapascal. After 8 days of withholding water, Psi/sub w/ at midafternoon decline to -0.9 and -2.4 megapascals in cowpea and pigeonpea, respectively. The solute component of water potential (Psi/sub s/) decreased substantially less in cowpea than pigeonpea. Photosynthetic CER at saturation photon flux density (PFD) and ambient external CO/sub 2/ concentration on day 5 of withholding decreased by 83 and 55% in cowpea and pigeonpea, respectively. When measured at external, CO/sub 2/ concentration in bulk air of 360 microliters per liter, the CER of cowpea had fully recovered to control levels 3 days after rewatering; however, at 970 microliters per liter the PFD-saturated CERS of both species were substantially lower than in controls, indicating residual impairment.« less

Cumulative potential hydrologic impacts of surface coal mining in the eastern Powder River structural basin, northeastern Wyoming

USGS Publications Warehouse

Martin, L.J.; Naftz, D.L.; Lowham, H.W.; Rankl, J.G.

1988-01-01

There are 16 existing and six proposed surface coal mines in the eastern Powder River structural basin of northeastern Wyoming. Coal mining companies predict water level declines of 5 ft or more in the Wasatch aquifer to extend form about 1,000 to about 2,000 ft beyond the mine pits. The predicted 5 ft water level decline in the Wyodak coal aquifer generally extends 4-8 mi beyond the lease areas. About 3,000 wells are in the area of potential cumulative water level declines resulting from all anticipated mining. Of these 3,000 wells, about 1,200 are outside the areas of anticipated mining: about 1,000 wells supply water for domestic or livestock uses, and about 200 wells supply water for municipal, industrial, irrigation, and miscellaneous uses. The 1,800 remaining wells are used by coal mining companies. Future surface coal mining probably will result in postmining groundwater of similar quality to that currently present in the study area. By use of geochemical modeling techniques, the results of a hypothetical reaction path exercise indicate the potential for marked improvements in postmining water quality because of chemical reactions as postmining groundwater with a large dissolved solids concentration (3,540 mg/L) moves into a coal aquifer with relatively small dissolved solids concentrations (910 mg/L). Results of the modeling exercise also indicate geochemical conditions that are most ideal for large decreases in dissolved solids concentrations in coal aquifers receiving recharge from a spoil aquifer. (Lantz-PTT)

Trends in Rocky Mountain amphibians and the role of beaver as a keystone species

USGS Publications Warehouse

Hossack, Blake R.; Gould, William R.; Patla, Debra A.; Muths, Erin L.; Daley, Rob; Legg, Kristin; Corn, P. Stephen

2015-01-01

Despite prevalent awareness of global amphibian declines, there is still little information on trends for many widespread species. To inform land managers of trends on protected landscapes and identify potential conservation strategies, we collected occurrence data for five wetland-breeding amphibian species in four national parks in the U.S. Rocky Mountains during 2002–2011. We used explicit dynamics models to estimate variation in annual occupancy, extinction, and colonization of wetlands according to summer drought and several biophysical characteristics (e.g., wetland size, elevation), including the influence of North American beaver (Castor canadensis). We found more declines in occupancy than increases, especially in Yellowstone and Grand Teton national parks (NP), where three of four species declined since 2002. However, most species in Rocky Mountain NP were too rare to include in our analysis, which likely reflects significant historical declines. Although beaver were uncommon, their creation or modification of wetlands was associated with higher colonization rates for 4 of 5 amphibian species, producing a 34% increase in occupancy in beaver-influenced wetlands compared to wetlands without beaver influence. Also, colonization rates and occupancy of boreal toads (Anaxyrus boreas) and Columbia spotted frogs (Rana luteiventris) were ⩾2 times higher in beaver-influenced wetlands. These strong relationships suggest management for beaver that fosters amphibian recovery could counter declines in some areas. Our data reinforce reports of widespread declines of formerly and currently common species, even in areas assumed to be protected from most forms of human disturbance, and demonstrate the close ecological association between beaver and wetland-dependent species.

Fasting insulin levels and cognitive decline in older women without diabetes.

PubMed

van Oijen, Marieke; Okereke, Olivia I; Kang, Jae Hee; Pollak, Michael N; Hu, Frank B; Hankinson, Susan E; Grodstein, Francine

2008-01-01

Type 2 diabetes has been associated with an increased risk of dementia. To assess possible independent effects of insulin, we investigated the relation of insulin levels to cognitive decline in nondiabetic women. Fasting plasma insulin levels were measured in mid-life in 1,416 nondiabetic Nurses' Health Study participants, who also completed cognitive testing that began 10 years later (current age: 70-75 years). Over 4 years, 3 assessments of general cognition, verbal memory, category fluency and attention were administered. Primary outcomes were the Telephone Interview for Cognitive Status (TICS) performance, the global score (average of all tests) and verbal memory (average of verbal recall tests). Linear mixed-effects models were used to calculate the association between insulin and cognitive decline. Higher insulin levels were associated with a faster decline on the TICS and verbal memory. For analysis, batch-specific quartiles of insulin levels were constructed. Compared to the lowest quartile, adjusted differences in the annual rates of decline (with 95% CI values in parentheses) for the second, third and fourth quartiles were: TICS, -0.06 (-0.16, 0.03), -0.14 (-0.24, -0.04), and -0.09 (-0.19, 0.01) points (p trend = 0.04); verbal memory, -0.01 (-0.04, 0.02), -0.05 (-0.08, -0.02), and -0.02 (-0.05, 0.01) units (p trend = 0.02). These associations remained after multivariable adjustment. Our study provides evidence for a potential role of higher fasting insulin levels in cognitive decline, possibly independent of diabetes. (c) 2008 S. Karger AG, Basel

Long-term association of food and nutrient intakes with cognitive and functional decline: a 13-year follow-up study of elderly French women.

PubMed

Vercambre, Marie-Noël; Boutron-Ruault, Marie-Christine; Ritchie, Karen; Clavel-Chapelon, Françoise; Berr, Claudine

2009-08-01

The objective of the present study was to determine the potential long-term impact of dietary habits on age-related decline among 4809 elderly women (born between 1925 and 1930) in the 'Etude Epidémiologique de Femmes de la Mutuelle Générale de l'Education Nationale' (E3N) study, a French epidemiological cohort. In 1993, an extensive diet history self-administered questionnaire was sent to all participants, and in 2006 another questionnaire on instrumental activities of daily living (IADL) and recent cognitive change was sent to a close relative or friend of each woman. Logistic models adjusted for socio-demographic, lifestyle and health factors were performed to evaluate associations between habitual dietary intakes and two outcomes of interest based on the informant response: recent cognitive decline and IADL impairment. Recent cognitive decline was associated with lower intakes of poultry, fish, and animal fats, as well as higher intakes of dairy desserts and ice-cream. IADL impairment was associated with a lower intake of vegetables. The odds of recent cognitive decline increased significantly with decreasing intake of soluble dietary fibre and n-3 fatty acids but with increasing intake of retinol. The odds of IADL impairment increased significantly with decreasing intakes of vitamins B2, B6 and B12. These results are consistent with a possible long-term neuroprotective effect of dietary fibre, n-3 polyunsaturated fats and B-group vitamins, and support dietary intervention to prevent cognitive decline.

Stressful life events and cognitive decline in late life: moderation by education and age. The Cache County Study.

PubMed

Tschanz, Joann T; Pfister, Roxane; Wanzek, Joseph; Corcoran, Chris; Smith, Ken; Tschanz, Brian T; Steffens, David C; Østbye, Truls; Welsh-Bohmer, Kathleen A; Norton, Maria C

2013-08-01

Stressful life events (SLE) have been associated with increased dementia risk, but their association with cognitive decline has been inconsistent. In a longitudinal population-based study of older individuals, we examined the association between SLE and cognitive decline, and the role of potential effect modifiers. A total of 2665 non-demented participants of the Cache County Memory Study completed an SLE questionnaire at Wave 2 and were revisited 4 and 7 years later. The events were represented via several scores: total number, subjective rating (negative, positive, and unexpected), and a weighted summary based on their impact. Cognition was assessed at each visit with the modified Mini-Mental State Exam. General linear models were used to examine the association between SLE scores and cognition. Effect modification by age, education, and APOE genotype was tested. Years of formal education (p = 0.006) modified the effect of number of SLE, and age (p = 0.009) modified the effect of negative SLE on the rate of cognitive decline. Faster decline was observed among those with fewer years of education experiencing more SLE and also among younger participants experiencing more negative SLE. There was no association between other indicators of SLE and cognitive decline. APOE genotype did not modify any of the aforementioned associations. The effects of SLE on cognition in late life are complex and vary by individual factors such as age and education. These results may explain some of the contradictory findings in the literature. Copyright © 2012 John Wiley & Sons, Ltd.

Effect of passive acoustic sampling methodology on detecting bats after declines from white nose syndrome

USGS Publications Warehouse

Coleman, Laci S.; Ford, W. Mark; Dobony, Christopher A.; Britzke, Eric R.

2014-01-01

Concomitant with the emergence and spread of white-nose syndrome (WNS) and precipitous decline of many bat species in North America, natural resource managers need modified and/or new techniques for bat inventory and monitoring that provide robust occupancy estimates. We used Anabat acoustic detectors to determine the most efficient passive acoustic sampling design for optimizing detection probabilities of multiple bat species in a WNS-impacted environment in New York, USA. Our sampling protocol included: six acoustic stations deployed for the entire duration of monitoring as well as a 4 x 4 grid and five transects of 5-10 acoustic units that were deployed for 6-8 night sample durations surveyed during the summers of 2011-2012. We used Program PRESENCE to determine detection probability and site occupancy estimates. Overall, the grid produced the highest detection probabilities for most species because it contained the most detectors and intercepted the greatest spatial area. However, big brown bats (Eptesicus fuscus) and species not impacted by WNS were detected easily regardless of sampling array. Endangered Indiana (Myotis sodalis) and little brown (Myotis lucifugus) and tri-colored bats (Perimyotis subflavus) showed declines in detection probabilities over our study, potentially indicative of continued WNS-associated declines. Identification of species presence through efficient methodologies is vital for future conservation efforts as bat populations decline further due to WNS and other factors.   

Changes in Adolescents’ Receipt of Sex Education, 2006–2013

PubMed Central

Lindberg, Laura Duberstein; Maddow-Zimet, Isaac; Boonstra, Heather

2016-01-01

Purpose Updated estimates of adolescents’ receipt of sex education are needed to monitor changing access to information. Methods Using nationally representative data from the 2006–2010 and 2011–2013 National Survey of Family Growth, we estimated changes over time in adolescents’ receipt of sex education from formal sources and from parents and differentials in these trends by adolescents’ gender, race/ethnicity, age, and place of residence. Results Between 2006–2010 and 2011–2013, there were significant declines in adolescent females’ receipt of formal instruction about birth control (70% to 60%), saying no to sex (89% to 82%), sexually transmitted disease (94% to 90%), and HIV/AIDS (89% to 86%). There was a significant decline in males’ receipt of instruction about birth control (61% to 55%). Declines were concentrated among adolescents living in nonmetropolitan areas. The proportion of adolescents talking with their parents about sex education topics did not change significantly. Twenty-one percent of females and 35% of males did not receive instruction about methods of birth control from either formal sources or a parent. Conclusions Declines in receipt of formal sex education and low rates of parental communication may leave adolescents without instruction, particularly in nonmetropolitan areas. More effort is needed to understand this decline and to explore adolescents’ potential other sources of reproductive health information. PMID:27032487

Conservation genetics of extremely isolated urban populations of the northern dusky salamander (Desmognathus fuscus) in New York City

PubMed Central

Zak, Yana; Pehek, Ellen

2013-01-01

Urbanization is a major cause of amphibian decline. Stream-dwelling plethodontid salamanders are particularly susceptible to urbanization due to declining water quality and hydrological changes, but few studies have examined these taxa in cities. The northern dusky salamander (Desmognathus fuscus) was once common in the New York City metropolitan area, but has substantially declined throughout the region in recent decades. We used five tetranucleotide microsatellite loci to examine population differentiation, genetic variation, and bottlenecks among five remnant urban populations of dusky salamanders in NYC. These genetic measures provide information on isolation, prevalence of inbreeding, long-term prospects for population persistence, and potential for evolutionary responses to future environmental change. All populations were genetically differentiated from each other, and the most isolated populations in Manhattan have maintained very little genetic variation (i.e. <20% heterozygosity). A majority of the populations also exhibited evidence of genetic bottlenecks. These findings contrast with published estimates of high genetic variation within and lack of structure between populations of other desmognathine salamanders sampled over similar or larger spatial scales. Declines in genetic variation likely resulted from population extirpations and the degradation of stream and terrestrial paths for dispersal in NYC. Loss of genetic variability in populations isolated by human development may be an underappreciated cause and/or consequence of the decline of this species in urbanized areas of the northeast USA. PMID:23646283

Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population.

PubMed

Hoffman, J I; Kowalski, G J; Klimova, A; Eberhart-Phillips, L J; Staniland, I J; Baylis, A M M

2016-07-01

Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations.

How family members manage risk around functional decline: the autonomy management process in households facing dementia.

PubMed

Berry, Brandon; Apesoa-Varano, Ester Carolina; Gomez, Yarin

2015-04-01

Most dementia research investigates the social context of declining ability through studies of decision-making around medical treatment and end-of-life care. This study seeks to fill an important gap in research about how family members manage the risks of functional decline at home. Drawing on three waves of in-depth interviewing in 2012-2014, it investigates how family members in US households manage decline in an affected individual's natural range of daily activities over time. The findings show that early on in the study period affected individuals were perceived to have awareness of their decline and routinely drew on family members for support. Support transformed when family members detected that the individual's deficit awareness had diminished, creating a corresponding increase in risk of self-harm around everyday activities. With a loss of confidence in the individual's ability to regulate his or her own activities to avoid these risks, family members employed unilateral practices to manage the individual's autonomy around his or her activity involvements. These practices typically involved various deceits and ruses to discourage elders from engaging in activities perceived as potentially dangerous. The study concludes by discussing the implications that the social context of interpretive work around awareness and risk plays an important role in how families perceive an elder's functional ability and manage his or her activity involvements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Population structure and historical demography of South American sea lions provide insights into the catastrophic decline of a marine mammal population

PubMed Central

Hoffman, J. I.; Kowalski, G. J.; Klimova, A.; Staniland, I. J.; Baylis, A. M. M.

2016-01-01

Understanding the causes of population decline is crucial for conservation management. We therefore used genetic analysis both to provide baseline data on population structure and to evaluate hypotheses for the catastrophic decline of the South American sea lion (Otaria flavescens) at the Falkland Islands (Malvinas) in the South Atlantic. We genotyped 259 animals from 23 colonies across the Falklands at 281 bp of the mitochondrial hypervariable region and 22 microsatellites. A weak signature of population structure was detected, genetic diversity was moderately high in comparison with other pinniped species, and no evidence was found for the decline being associated with a strong demographic bottleneck. By combining our mitochondrial data with published sequences from Argentina, Brazil, Chile and Peru, we also uncovered strong maternally directed population structure across the geographical range of the species. In particular, very few shared haplotypes were found between the Falklands and South America, and this was reflected in correspondingly low migration rate estimates. These findings do not support the prominent hypothesis that the decline was caused by migration to Argentina, where large-scale commercial harvesting operations claimed over half a million animals. Thus, our study not only provides baseline data for conservation management but also reveals the potential for genetic studies to shed light upon long-standing questions pertaining to the history and fate of natural populations. PMID:27493782

How family members manage risk around functional decline: The autonomy management process in households facing dementia

PubMed Central

Berry, Brandon; Apesoa-Varano, Ester Carolina; Gomez, Yarin

2015-01-01

Most dementia research investigates the social context of declining ability through studies of decision-making around medical treatment and end-of-life care. This study seeks to fill an important gap in research about how family members manage the risks of functional decline at home. Drawing on three waves of retrospective interviewing in 2012–2014, it investigates how family members in US households manage decline in an affected individual’s natural range of daily activities over time. The findings show that early on in the study period affected individuals were perceived to have awareness of their decline and routinely drew on family members for support. Support transformed when family members detected that the individual’s deficit awareness had diminished, creating a corresponding increase in risk of self-harm around everyday activities. With a loss of confidence in the individual’s ability to regulate his or her own activities to avoid these risks, family members employed unilateral practices to manage the individual’s autonomy around his or her activity involvements. These practices typically involved various deceits and ruses to discourage elders from engaging in activities perceived as potentially dangerous. The study concludes by discussing the implications that the social context of interpretive work around awareness and risk plays an important role in how families perceive an elder’s functional ability and manage his or her activity involvements. PMID:25697634

The Nordic Prudent Diet Reduces Risk of Cognitive Decline in the Swedish Older Adults: A Population-Based Cohort Study.

PubMed

Shakersain, Behnaz; Rizzuto, Debora; Larsson, Susanna C; Faxén-Irving, Gerd; Fratiglioni, Laura; Xu, Wei-Li

2018-02-17

Appropriate dietary pattern for preserving cognitive function in northern Europe remains unknown. We aimed to identify a Nordic dietary pattern index associated with slower cognitive decline compared to the Mediterranean-DASH Intervention for Neurodegenerative Delay, Mediterranean Diet, Dietary Approaches to Stop Hypertension, and Baltic Sea Diet indices. A total of 2223 dementia-free adults aged ≥60 were followed for 6 years. Mini-Mental State Examination was administrated at baseline and follow-ups. Dietary intake was assessed by 98-item food frequency questionnaire, and the Nordic Prudent Dietary Pattern (NPDP) was identified. Data were analysed using mixed-effects and parametric survival models and receiver operating characteristic curves with adjustment for potential confounders. Moderate (β = 0.139, 95% CI 0.077-0.201) and high adherence (β = 0.238, 95% CI 0.175-0.300) to NPDP were associated with less cognitive decline compared to other four indices. High adherence to NPDP was also associated with the lowest risk of MMSE decline to ≤24 (HR = 0.176, 95% CI 0.080-0.386) and had the greatest ability to predict such decline (area under the curve = 0.70). Moderate-to-high adherence to the NPDP may predict a better-preserved cognitive function among older adults in Nordic countries. Regional dietary habits should be considered in developing dietary guidelines for the prevention of cognitive impairment and dementia.

Hydrogeology of parts of the Central Platte and Lower Loup Natural Resources Districts, Nebraska

USGS Publications Warehouse

Peckenpaugh, J.M.; Dugan, J.T.

1983-01-01

Water-level declines of at least 15 feet have occurred in this heavily irrigated area of central Nebraska since the 1930's, and potential for additonal declines is high. To test the effects of additional irrigation development on water levels and streamflow , computer programs were developed that represent the surface-water system, soil zone, and saturated zone. A two-dimensional, finite-difference ground-water flow model of the 3,374 square-mile study area was developed and calibrated using steady-state and transient conditions. Three management alternatives were examined. First, 125,000 acre-feet of water would be diverted annually from the Platte River. During a water year in which flows are similar to those in 1957, months of zero streamflow at Grand Island increased from the historical 2, to 7. After 5 years of such low flows, in 36 nodes (997.4 acres per node) water levels declined more than 5 feet, with a maximum decline of 10.7 feet. A second alternative would allow no new ground-water development after 1980. The third alternative would allow irrigable but unirrigated land to be developed at an annual rate of 2, 5, and 8 percent and to apply irrigation water at 80, 100, and 120 percent of consumptive irrigation requirements. The maximum projected declines by 2020 are 119 and 139 feet, respectively, for the second and third alternatives. (USGS)

Trouble in the aquatic world: How wildlife professionals are battling amphibian declines

USGS Publications Warehouse

Olson, Deanna H.; Chestnut, Tara E.

2014-01-01

A parasitic fungus, similar to the one that caused the extinction of numerous tropical frog and toad species, is killing salamanders in Europe. Scientists first identified the fungus, Batrachochytrium salamandrivorans, in 2013 as the culprit behind the death of fire salamanders (Salamandra salamandra) in the Netherlands (Martel et al. 2013) and are now exploring its potential impact to other species. Although the fungus, which kills the amphibians by infecting their skin, has not yet spread to the United States, researchers believe it’s only a matter of time before it does and, when that happens, the impact on salamander populations could be devastating (Martel et al. 2014).Reports of worldwide declines of amphibians began a quarter of a century ago (Blaustein & Wake 1990). Globally, some amphibian population declines occurred in the late 1950s and early 1960s, and declining trends continued in North America (Houlahan et al. 2000). In the earlier years, population declines were attributed primarily to overharvest due to unregulated supply of species such as the northern leopard frog (Lithobates pipiens) for educational use (Dodd 2013). In later years, however, causes of declines were less evident. In 1989, herpetologists at the First World Congress of Herpetology traded alarming stories of losses across continents and in seemingly protected landscapes, making it clear that amphibian population declines were a “global phenomenon.” In response to these reports, in 1991, the International Union for Conservation of Nature (IUCN) established the Declining Amphibian Populations Task Force to better understand the scale and scope of global amphibian declines. Unfortunately, the absence of long-term monitoring data and targeted studies made it difficult for the task force to compile information.Today, according to AmphibiaWeb.org, there are 7,342 amphibian species in the world — double the number since the first alerts of declines — making the situation appear deceptively less dire. In fact, our understanding of genetic diversity significantly raises the stakes, and we are at risk of losing far more species than we believed only a few years ago. According to the IUCN, amphibians now lead the list of vertebrate taxa affected by the larger “biodiversity crisis” and sixth major mass- extinction event on Earth (Keith et al. 2014, Wake and Vredenburg 2008).

Reversing the Literacy Decline by Controlling the Electronic Demons.

ERIC Educational Resources Information Center

Shenkman, Harriet

1985-01-01

Computer games, rock video, television, and movies are robbing teenagers of time they should be using to develop their minds. However, the electronic media do have a positive potential. A 10-item reference list is provided. (Author/DCS)

77 FR 27386 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-10

... ecology, population distribution and status, and actual and potential causes of decline was included in.... 764). Human activities that can impact the hyporheic zone include water diversions, sedimentation from...

Enhanced biodiversity and pollination in UK agroforestry systems.

PubMed

Varah, Alexa; Jones, Hannah; Smith, Jo; Potts, Simon G

2013-07-01

Monoculture farming systems have had serious environmental impacts such as loss of biodiversity and pollinator decline. The authors explain how temperate agroforestry systems show potential in being able to deliver multiple environmental benefits. © 2013 Society of Chemical Industry.

The effect of changes in hospital reimbursement on nurse staffing decisions at safety net and nonsafety net hospitals.

PubMed

Lindrooth, Richard C; Bazzoli, Gloria J; Needleman, Jack; Hasnain-Wynia, Romana

2006-06-01

The financial savings from the Balanced Budget Act (BBA) are attractive to policy makers, but such savings come at a cost. We measure changes in nurse staffing at hospitals related to potential declines in reimbursement through the BBA. Following Hadley, Zuckerman, and Feder (1989), we define a fiscal pressure index (FPI) to measure the differential effect of the BBA. We estimate the effect of the FPI on the number of full-time equivalent registered nurses (RN) and licensed practical nurses (LPN) per adjusted patient day using American Hospital Association (AHA) data of a panel of hospitals from 1996 to 2001. The AHA data are combined with the Area Resource Files and health maintenance organizations penetration data. We control for hospital heterogeneity using fixed effects. All urban short-term general hospitals that responded to the staffing and uncompensated care questions in the AHA survey between 1996 and 2001. We define safety net hospitals as those with a high ratio of uncompensated costs to total hospital expenses (see, e.g., Zuckerman et al. 2001). We find that the nonsafety net hospitals that were most susceptible to the provisions of the BBA experienced a decline in RN staffing ratios about twice the rate of the nonsafety net hospitals that were least susceptible to the BBA. We are unable to detect an effect of the BBA on staffing at safety net hospitals. RN and LPN staffing levels per adjusted patient day declined, on average, between 1996 and 2001. Within the context of the general decline, we find that RN staffing per adjusted patient day declined even more at nonsafety net hospitals that were most susceptible to lower reimbursement related to the BBA. Thus, there was a small but statistically significant incremental effect of potential BBA losses on RN staffing at hospitals that were expected to be affected most. This incremental decline represented about a 6 percent increase in nurse workload that in isolation might not affect quality. Nevertheless, the BBA contributed to the contemporaneous trends toward higher nurse workloads that could have deleterious effects on quality. In contrast, safety net hospitals did not respond to the provisions of the BBA by reducing staffing ratios. This conclusion is tempered by the fact that we have few safety net hospitals in the sample.

The NEIL Memory Research Unit: psychosocial, biological, physiological and lifestyle factors associated with healthy ageing: study protocol.

PubMed

Hannigan, Caoimhe; Coen, Robert F; Lawlor, Brian A; Robertson, Ian H; Brennan, Sabina

2015-01-01

Population ageing is a global phenomenon that has characterised demographic trends during the 20th and 21st century. The rapid growth in the proportion of older adults in the population, and resultant increase in the incidence of age-related cognitive decline, dementia and Alzheimer's disease, brings significant social, economic and healthcare challenges. Decline in cognitive abilities represents the most profound threat to active and healthy ageing. Current evidence suggests that a significant proportion of cases of age-related cognitive decline and dementia may be preventable through the modification of risk factors including education, depressive symptomology, physical activity, social engagement and participation in cognitively stimulating activities. The NEIL Memory Research Unit cohort study was established to investigate factors related to brain health and the maintenance of cognitive function. A cohort of 1000 normally ageing adults aged 50 years and over are being recruited to participate in comprehensive assessments at baseline, and at follow-up once every 2 years. The assessment protocol comprises a comprehensive neuropsychological battery, some basic physical measures, psychosocial scales, questionnaire measures related to a range of health, lifestyle and behavioural factors, and a measure of resting state activity using electroencephalography (EEG). The NEIL Memory Research Unit cohort study will address key questions about brain health and cognitive ageing in the population aged 50+, with a particular emphasis on the influence of potentially modifiable factors on cognitive outcomes. Analyses will be conducted with a focus on factors involved in the maintenance of cognitive function among older adults, and therefore will have the potential to contribute significant knowledge related to key questions within the field of cognitive ageing, and to inform the development of public health interventions aimed at preventing cognitive decline and promoting active and healthy ageing.

Voluntary Running Prevents Progressive Memory Decline and Increases Adult Hippocampal Neurogenesis and Growth Factor Expression After Whole-Brain Irradiation

PubMed Central

Wong-Goodrich, Sarah J.E.; Pfau, Madeline L.; Flores, Catherine T.; Fraser, Jennifer A.; Williams, Christina L.; Jones, Lee W.

2010-01-01

Whole-brain irradiation (WBI) therapy produces progressive learning and memory deficits in patients with primary or secondary brain tumors. Exercise enhances memory and adult hippocampal neurogenesis in the intact brain, so we hypothesized that exercise may be an effective treatment to alleviate consequences of WBI. Previous studies using animal models to address this issue have yielded mixed results and have not examined potential molecular mechanisms. We investigated the short- and long-term effects of WBI on spatial learning and memory retention, and determined whether voluntary running after WBI aids recovery of brain and cognitive function. Forty adult female C57Bl/6 mice given a single dose of 5 Gy or sham WBI were trained 2.5 weeks and up to four months after WBI in a Barnes maze. Half of the mice received daily voluntary wheel access starting one month after sham- or WBI. Daily running following WBI prevented the marked decline in spatial memory retention observed months after irradiation. Bromodeoxyuridine (BrdU) immunolabeling and ELISA indicated that this behavioral rescue was accompanied by a partial restoration of newborn BrdU+/NeuN+ neurons in the dentate gyrus and increased hippocampal expression of brain-derived vascular endothelial growth factor and insulin-like growth factor, and occurred despite irradiation-induced elevations in hippocampal pro-inflammatory cytokines. WBI in adult mice produced a progressive memory decline consistent with what has been reported in cancer patients receiving WBI therapy. Our findings show that running can abrogate this memory decline and aid recovery of adult hippocampal plasticity, thus highlighting exercise as a potential therapeutic intervention. PMID:20884629

Decline in global oceanic oxygen content during the past five decades.

PubMed

Schmidtko, Sunke; Stramma, Lothar; Visbeck, Martin

2017-02-15

Ocean models predict a decline in the dissolved oxygen inventory of the global ocean of one to seven per cent by the year 2100, caused by a combination of a warming-induced decline in oxygen solubility and reduced ventilation of the deep ocean. It is thought that such a decline in the oceanic oxygen content could affect ocean nutrient cycles and the marine habitat, with potentially detrimental consequences for fisheries and coastal economies. Regional observational data indicate a continuous decrease in oceanic dissolved oxygen concentrations in most regions of the global ocean, with an increase reported in a few limited areas, varying by study. Prior work attempting to resolve variations in dissolved oxygen concentrations at the global scale reported a global oxygen loss of 550 ± 130 teramoles (10 12  mol) per decade between 100 and 1,000 metres depth based on a comparison of data from the 1970s and 1990s. Here we provide a quantitative assessment of the entire ocean oxygen inventory by analysing dissolved oxygen and supporting data for the complete oceanic water column over the past 50 years. We find that the global oceanic oxygen content of 227.4 ± 1.1 petamoles (10 15  mol) has decreased by more than two per cent (4.8 ± 2.1 petamoles) since 1960, with large variations in oxygen loss in different ocean basins and at different depths. We suggest that changes in the upper water column are mostly due to a warming-induced decrease in solubility and biological consumption. Changes in the deeper ocean may have their origin in basin-scale multi-decadal variability, oceanic overturning slow-down and a potential increase in biological consumption.

Decline in extractable antibiotics in manure-based composts during composting.

PubMed

Kim, K-R; Owens, G; Ok, Y S; Park, W-K; Lee, D B; Kwon, S-I

2012-01-01

A wide variety of antibiotics have been detected in natural water samples and this is of potential concern because of the adverse environmental effects of such antibiotic residues. One of the main sources of antibiotics effluence to the surrounding environment is livestock manures which often contain elevated concentrations of veterinary antibiotics (VAs) which survive digestion in the animal stomach following application in animal husbandry practices. In Korea, livestock manures are normally used for compost production indicating that there is potential for antibiotic release to the environment through compost application to agricultural lands. Therefore, reduction of the amount of VAs in composts is crucial. The purpose of this study was to understand the influence of the composting process and the components of the compost on the levels of three common classes of antibiotics (tetracyclines, sulfonamides, and macrolides). Composted materials at different stages of composting were collected from compost manufacturing plants and the variation in antibiotic concentrations was determined. Three different antibiotics, chlortetracycline (CTC), sulfamethazine (SMZ), and tylosin (TYL) at three different concentrations (2, 10, and 20mgkg(-1)) were also applied to a mixture of pig manure and sawdust and the mixtures incubated using a laboratory scale composting apparatus to monitor the changes in antibiotic concentrations during composting together with the physicochemical properties of the composts. During composting, in both field and lab-scale investigations, the concentrations of all three different antibiotics declined below the relevant Korean guideline values (0.8mgkg(-1) for tetracyclines, 0.2mgkg(-1) for sulfonamides and 1.0mgkg(-1) for macrolides). The decline of tetracycline and sulfonamide concentrations was highly dependent on the presence of sawdust while there was no influence of sawdust on TYL decline. Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessing Decline: Visualising Progression in Huntington's Disease using a Clinical Dashboard with Enroll-HD Data.

PubMed

Walker, Thomas; Ghosh, Boyd; Kipps, Christopher

2017-01-01

In Huntington's disease (HD), it remains unclear how symptom severity and rate of symptomatic change relates to age and CAG repeat number (CAGn). It is often difficult for clinicians to assess whether an affected individual's symptoms are progressing at a similar rate to their affected peers, limiting their ability to intervene at the most appropriate time. To develop a clinical dashboard that compares an individual's total motor score (TMS), total functional capacity (TFC) and symbol digit modality test (SDMT) scores against a global cohort, controlling for age and CAGn. The dashboard could then be used by clinicians to identify individuals progressing at a disproportionate rate to his or her peers. Annualised longitudinal clinical assessment scores from the Enroll-HD dataset were used to generate decline trajectories of the global cohort, allowing cross-sectional (TMS n = 734; TFC n = 734; SDMT n = 694) and longitudinal (TMS n = 270; TFC n = 270; SDMT n = 247) comparison with individual clinical symptom rating scores, to assess decline relative to affected peers. An electronic dashboard with a dynamic output display was created that rapidly compares clinical symptom rating scores of a specific individual against affected peers from a global cohort of comparable CAGn. This study shows the potential for use of multi-centre trial data in allowing comparison of the individual to a larger group to facilitate improved decision-making for individual patients. Visualisation of these metrics via a clinical dashboard demonstrates how it may aid identification of those with disproportionate decline, offering potential for intervention at specific critical points in the disease course.

Cinnamon polyphenols attenuate cell swelling and mitochondrial dysfunction following oxygen-glucose deprivation in glial cells.

PubMed

Panickar, Kiran S; Polansky, Marilyn M; Anderson, Richard A

2009-04-01

Astrocyte swelling is an integral component of cytotoxic brain edema in ischemic injury. While mechanisms underlying astrocyte swelling are likely multifactorial, oxidative stress and mitochondrial dysfunction are hypothesized to contribute to such swelling. We investigated the protective effects of cinnamon polyphenol extract (CPE) that has anti-oxidant and insulin-potentiating effects on cell swelling and depolarization of the inner mitochondrial membrane potential (DeltaPsi(m)) in ischemic injury. C6 glial cells were subjected to oxygen-glucose deprivation (OGD) and cell volume determined using the 3-O-methyl-[3H]-glucose method at 90 min after the end of OGD. When compared with controls, OGD increased cell volume by 34%. This increase was blocked by CPE or insulin but not by blockers of oxidative/nitrosative stress including vitamin E, resveratrol, N-nitro-L-arginine methyl ester (L-NAME) or uric acid. Mitochondrial dysfunction, a key component of ischemic injury, contributes to cell swelling. Changes in DeltaPsi(m) were assessed at the end of OGD with tetramethylrhodamine ethyl ester (TMRE), a potentiometric dye. OGD induced a 39% decline in DeltaPsi(m) and this decline was blocked by CPE as well as insulin. To test the involvement of the mitochondrial permeability transition (mPT), we used Cyclosporin A (CsA), an immunosuppressant and a blocker of the mPT pore. CsA blocked cell swelling and the decline in DeltaPsi(m) but FK506, an immunosuppressant that does not block the mPT, did not. Our results show that CPE reduces OGD-induced cell swelling as well as the decline in DeltaPsi(m) in cultures and some of its protective effects may be through inhibiting the mPT.

Epigenetic alterations in the suprachiasmatic nucleus and hippocampus contribute to age-related cognitive decline

PubMed Central

Deibel, Scott H.; Zelinski, Erin L.; Keeley, Robin J.; Kovalchuk, Olga; McDonald, Robert J.

2015-01-01

Circadian rhythm dysfunction and cognitive decline, specifically memory loss, frequently accompany natural aging. Circadian rhythms and memory are intertwined, as circadian rhythms influence memory formation and recall in young and old rodents. Although, the precise relationship between circadian rhythms and memory is still largely unknown, it is hypothesized that circadian rhythm disruption, which occurs during aging, contributes to age-associated cognitive decline, specifically memory loss. While there are a variety of mechanisms that could mediate this effect, changes in the epigenome that occur during aging has been proposed as a potential candidate. Interestingly, epigenetic mechanisms, such as DNA methylation and sirtuin1 (SIRT1) are necessary for both circadian rhythms and memory. During aging, similar alterations of epigenetic mechanisms occur in the suprachiasmatic nucleus (SCN) and hippocampus, which are necessary for circadian rhythm generation and memory, respectively. Recently, circadian rhythms have been linked to epigenetic function in the hippocampus, as some of these epigenetic mechanisms oscillate in the hippocampus and are disrupted by clock gene deletion. The current paper will review how circadian rhythms and memory change with age, and will suggest how epigenetic changes in these processes might contribute to age-related cognitive decline. PMID:26252151

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS.

PubMed

Foley, Jennifer A; Foltynie, Tom; Zrinzo, Ludvic; Hyam, Jonathan A; Limousin, Patricia; Cipolotti, Lisa

2017-01-01

Objective . Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS) for Parkinson's disease (PD). The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed. Method . In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS. Results . As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed. Discussion . Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS.

Declining Radial Growth Response of Coastal Forests to Hurricanes and Nor'easters

NASA Astrophysics Data System (ADS)

Fernandes, Arnold; Rollinson, Christine R.; Kearney, William S.; Dietze, Michael C.; Fagherazzi, Sergio

2018-03-01

The Mid-Atlantic coastal forests in Virginia are stressed by episodic disturbance from hurricanes and nor'easters. Using annual tree ring data, we adopt a dendroclimatic and statistical modeling approach to understand the response and resilience of a coastal pine forest to extreme storm events, over the past few decades. Results indicate that radial growth of trees in the study area is influenced by age, regional climate trends, and individual tree effects but dominated periodically by growth disturbance due to storms. We evaluated seven local extreme storm events to understand the effect of nor'easters and hurricanes on radial growth. A general decline in radial growth was observed in the year of the extreme storm and 3 years following it, after which the radial growth started recovering. The decline in radial growth showed a statistically significant correlation with the magnitude of the extreme storm (storm surge height and wind speed). This study contributes to understanding declining tree growth response and resilience of coastal forests to past disturbances. Given the potential increase in hurricanes and storm surge severity in the region, this can help predict vegetation response patterns to similar disturbances in the future.

Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset.

PubMed

Wootton, J Timothy; Pfister, Catherine A; Forester, James D

2008-12-02

Increasing global concentrations of atmospheric CO(2) are predicted to decrease ocean pH, with potentially severe impacts on marine food webs, but empirical data documenting ocean pH over time are limited. In a high-resolution dataset spanning 8 years, pH at a north-temperate coastal site declined with increasing atmospheric CO(2) levels and varied substantially in response to biological processes and physical conditions that fluctuate over multiple time scales. Applying a method to link environmental change to species dynamics via multispecies Markov chain models reveals strong links between in situ benthic species dynamics and variation in ocean pH, with calcareous species generally performing more poorly than noncalcareous species in years with low pH. The models project the long-term consequences of these dynamic changes, which predict substantial shifts in the species dominating the habitat as a consequence of both direct effects of reduced calcification and indirect effects arising from the web of species interactions. Our results indicate that pH decline is proceeding at a more rapid rate than previously predicted in some areas, and that this decline has ecological consequences for near shore benthic ecosystems.

Chloroplast Osmotic Adjustment and Water Stress Effects on Photosynthesis 1

PubMed Central

Gupta, Ashima Sen; Berkowitz, Gerald A.

1988-01-01

Previous studies have suggested that chloroplast stromal volume reduction may mediate the inhibition of photosynthesis under water stress. In this study, the effects of spinach (Spinacia oleracea, var `Winter Bloomsdale') plant water deficits on chloroplast photosynthetic capacity, solute concentrations in chloroplasts, and chloroplast volume were studied. In situ (gas exchange) and in vitro measurements indicated that chloroplast photosynthetic capacity was maintained during initial leaf water potential (Ψw) and relative water content (RWC) decline. During the latter part of the stress period, photosynthesis dropped precipitously. Chloroplast stromal volume apparently remained constant during the initial period of decline in RWC, but as leaf Ψw reached −1.2 megapascals, stromal volume began to decline. The apparent maintenance of stromal volume over the initial RWC decline during a stress cycle suggested that chloroplasts are capable of osmotic adjustment in response to leaf water deficits. This hypothesis was confirmed by measuring chloroplast solute levels, which increased during stress. The results of these experiments suggest that stromal volume reduction in situ may be associated with loss of photosynthetic capacity and that one mechanism of photosynthetic acclimation to low Ψw may involve stromal volume maintenance. PMID:16666266

Race and incarceration in an aging cohort of Vietnam veterans in treatment for post-traumatic stress disorder (PTSD).

PubMed

Coker, Kendell L; Rosenheck, Robert

2014-03-01

Cross sectional studies have addressed the incarceration of Vietnam veterans with post-traumatic stress disorder (PTSD), but no studies have examined changes in incarceration as they age. This study examines patterns of incarceration among Vietnam veterans treated in specialized veterans affairs (VA) intensive PTSD programs over time. Data was drawn from admission data from the initial episode of treatment of Caucasian and African American Vietnam veterans entering VA specialized intensive PTSD programs between 1993 and 2011 (N = 31,707). Bivariate correlations and logistic regression were used to examine associations among race and incarceration over time and the potentially confounding influence of demographic and clinical covariates on this relationship. Rates of reported incarceration declined from 63 to 43%. Over time, African American veterans were 34% more likely than Caucasian veterans to have a lifetime history of incarceration while interaction analysis showed steeper declines for Caucasians than African Americans. Rates of incarceration among these Vietnam veterans declined as they aged. Furthermore, African American veterans were substantially more likely than Caucasian veterans to have been incarcerated and showed less decline as the cohort aged. While reduced, needs for clinical PTSD services remain among aging combat veterans.

Do yield and quality of big bluestem and switchgrass feedstock decline over winter?

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerdardii Vitman) are potential bioenergy feedstocks for thermochemical platforms. Feedstock storage, fall harvest constraints, and environmental benefits provided by perennials are rationales for developing localized perennial feedstock...

POPULATION DECLINE IN STREAM FISH

EPA Science Inventory

Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

HOW FAR TO THE NEAREST ROAD?

EPA Science Inventory

Increases in impervious surface area lead to declines in chemical and biological indicators of water quality .Roads are an important aspect of impervious surface, and distance to roads is an indicator of the potential threat to aquatic and terrestrial ecosystems. Although roads a...

Recent fertility trends in industrialized countries: toward a fluctuating or a stable pattern?

PubMed

Day, L H

1995-09-01

The conclusion of this analysis of fertility trends in industrialized countries is that future trends will be evident from accurate data and the inclusion of causal factors such as religion, ethnicity, migration status, marital status, employment status, neighborhood residence, or housing type. Period fertility measures are considered to be unreliable but useful as indicators of potential future changes in fertility. The expectation is that developed countries with low birth rates will have greater fluctuations than trends. Current patterns of fertility in developed countries are thought to have occurred due to substantial control over both the number and the timing of fertility. Patterns in the recent past have reflected further decline, an end to decline and a continued increase, or fluctuation. The most widespread pattern is continued increase following a period of low fertility. This pattern is in evidence in almost every country of northern and western Europe, Canada, the United States, and New Zealand. Countries with continued declines include Japan and eastern and southern European countries, which were the last to experience declines to replacement levels. Countries with fluctuating patterns include Norway, Sweden, and Switzerland. Countries with greater fluctuations include Belgium, Iceland, the former West Germany, the Netherlands, and Poland. The argument is made to not count these patterns as fluctuations due to 1) the similarity in magnitude, timing, and direction; 2) the small changes after the low was reached; and 3) their appearance everywhere at the same time. Stability of rates in the future appears to be a reasonable prospect due to the greater openness about human sexuality and the wider roles for women. Changes have occurred in attitudes about family size in the direction of smaller families, and the range in family size has narrowed considerably. Potential increases may occur due to a new emphasis on family and parenthood, the diminished impact of divorce on childbearing, and greater emotional value placed on children, potential dissatisfaction among women in the work force, and loss of interest in acquisition of consumer items and satiety of human wants.

Intravenous injection of pharmaceutical tablets presenting as multiple pulmonary nodules and declining pulmonary function in an adolescent with cystic fibrosis.

PubMed

Smith, Kelly J; Elidemir, Okan; Dishop, Megan K; Eldin, Karen W; Tatevian, Nina; Moore, Robert H

2006-09-01

Here we present the unusual case of an adolescent with cystic fibrosis presenting with declining pulmonary function and diffuse micronodular pulmonary disease. This case illustrates the radiographic and pathologic findings associated with the intravenous injection and pulmonary arterial embolization of insoluble pharmaceutical-tablet constituents. The number of first-time users reporting nonmedical use of prescription pain relievers is increasing dramatically, especially in adolescents. Recognition of both the diagnostic imaging features and histologic features on lung biopsy are critical steps for early diagnosis, intervention, and potential prevention of sudden death in these at-risk patients.

Implications of psychoactive 'bath salts' use during pregnancy.

PubMed

Gray, Bobbe Ann; Holland, Cindra

2014-01-01

Psychoactive bath salts (PABS) comprise a group of highly dangerous designer drugs showing a sharp escalation in reported U.S. exposures from 2010 through 2012, following rapid spread of the drug in Europe. Since a federal ban on the major ingredients in October 2011, numbers have declined. However, evidence from the United Kingdom shows an initial decline after the UK ban in 2010 with a 400 percent increase in reports by 2012. Actual information about the effect of PABS use on pregnant women and fetuses is almost nonexistent. Clinicians should be aware of the potential maternal, fetal and neonatal effects of PABS. © 2014 AWHONN.

Potential soil carbon sequestration in overgrazed grassland ecosystems

NASA Astrophysics Data System (ADS)

Conant, Richard T.; Paustian, Keith

2002-12-01

Excessive grazing pressure is detrimental to plant productivity and may lead to declines in soil organic matter. Soil organic matter is an important source of plant nutrients and can enhance soil aggregation, limit soil erosion, and can also increase cation exchange and water holding capacities, and is, therefore, a key regulator of grassland ecosystem processes. Changes in grassland management which reverse the process of declining productivity can potentially lead to increased soil C. Thus, rehabilitation of areas degraded by overgrazing can potentially sequester atmospheric C. We compiled data from the literature to evaluate the influence of grazing intensity on soil C. Based on data contained within these studies, we ascertained a positive linear relationship between potential C sequestration and mean annual precipitation which we extrapolated to estimate global C sequestration potential with rehabilitation of overgrazed grassland. The GLASOD and IGBP DISCover data sets were integrated to generate a map of overgrazed grassland area for each of four severity classes on each continent. Our regression model predicted losses of soil C with decreased grazing intensity in drier areas (precipitation less than 333 mm yr-1), but substantial sequestration in wetter areas. Most (93%) C sequestration potential occurred in areas with MAP less than 1800 mm. Universal rehabilitation of overgrazed grasslands can sequester approximately 45 Tg C yr-1, most of which can be achieved simply by cessation of overgrazing and implementation of moderate grazing intensity. Institutional level investments by governments may be required to sequester additional C.

Whitebark pine, population density, and home-range size of grizzly bears in the greater Yellowstone ecosystem

USGS Publications Warehouse

Bjornlie, Daniel D.; van Manen, Frank T.; Ebinger, Michael R.; Haroldson, Mark A.; Thompson, Daniel J.; Costello, Cecily M.

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

Human activity and climate variability impacts on sediment discharge and runoff in the Yellow River of China

NASA Astrophysics Data System (ADS)

He, Yi; Wang, Fei; Mu, Xingmin; Guo, Lanqin; Gao, Peng; Zhao, Guangju

2017-07-01

We analyze the variability of sediment discharge and runoff in the Hekou-Longmen segment in the middle reaches of the Yellow River, China. Our analysis is based on Normalized Difference Vegetation Index (NDVI), sediment discharge, runoff, and monthly meteorological data (1961-2010). The climate conditions are controlled via monthly regional average precipitation and potential evapotranspiration (ET0) that are calculated with the Penman-Monteith method. Data regarding water and soil conservation infrastructure and their effects were investigated as causal factors of runoff and sediment discharge changes. The results indicated the following conclusions: (1) The sediment concentration, sediment discharge, and annual runoff, varied considerably during the study period and all of these factors exhibited larger coefficients of variation than ET0 and precipitation. (2) Sediment discharge, annual runoff, and sediment concentration significantly declined over the study period in a linear fashion. This was accompanied by an increase in ET0 and decline in precipitation that were not significant. (3) Within paired years with similar precipitation and potential evapotranspiration conditions (SPEC), all pairs showed a decline in runoff, sediment discharge, and sediment concentration. (4) Human impacts in this region were markedly high as indicated by NDVI, and soil and water measurements, and especially the soil and water conservation infrastructure resulting in an approximately 312 Mt year-1 of sediment deposition during 1960-1999.

Whitebark Pine, Population Density, and Home-Range Size of Grizzly Bears in the Greater Yellowstone Ecosystem

PubMed Central

Bjornlie, Daniel D.; Van Manen, Frank T.; Ebinger, Michael R.; Haroldson, Mark A.; Thompson, Daniel J.; Costello, Cecily M.

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size. PMID:24520354

Can small island mountains provide relief from the Subtropical Precipitation Decline? Simulating future precipitation regimes for small island nations using high resolution Regional Climate Models.

NASA Astrophysics Data System (ADS)

Bowden, J.; Terando, A. J.; Misra, V.; Wootten, A.

2017-12-01

Small island nations are vulnerable to changes in the hydrologic cycle because of their limited water resources. This risk to water security is likely even higher in sub-tropical regions where anthropogenic forcing of the climate system is expected to lead to a drier future (the so-called `dry-get-drier' pattern). However, high-resolution numerical modeling experiments have also shown an enhancement of existing orographically-influenced precipitation patterns on islands with steep topography, potentially mitigating subtropical drying on windward mountain sides. Here we explore the robustness of the near-term (25-45 years) subtropical precipitation decline (SPD) across two island groupings in the Caribbean, Puerto Rico and the U.S. Virgin Islands. These islands, forming the boundary between the Greater and Lesser Antilles, significantly differ in size, topographic relief, and orientation to prevailing winds. Two 2-km horizontal resolution regional climate model simulations are used to downscale a total of three different GCMs under the RCP8.5 emissions scenario. Results indicate some possibility for modest increases in precipitation at the leading edge of the Luquillo Mountains in Puerto Rico, but consistent declines elsewhere. We conclude with a discussion of potential explanations for these patterns and the attendant risks to water security that subtropical small island nations could face as the climate warms.

Quantifying the Detrimental Impacts of Land-Use and Management Change on European Forest Bird Populations

PubMed Central

Wade, Amy S. I.; Barov, Boris; Burfield, Ian J.; Gregory, Richard D.; Norris, Ken; Butler, Simon J.

2013-01-01

The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health. PMID:23704997

Whitebark pine, population density, and home-range size of grizzly bears in the greater yellowstone ecosystem.

PubMed

Bjornlie, Daniel D; Van Manen, Frank T; Ebinger, Michael R; Haroldson, Mark A; Thompson, Daniel J; Costello, Cecily M

2014-01-01

Changes in life history traits of species can be an important indicator of potential factors influencing populations. For grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE), recent decline of whitebark pine (WBP; Pinus albicaulis), an important fall food resource, has been paired with a slowing of population growth following two decades of robust population increase. These observations have raised questions whether resource decline or density-dependent processes may be associated with changes in population growth. Distinguishing these effects based on changes in demographic rates can be difficult. However, unlike the parallel demographic responses expected from both decreasing food availability and increasing population density, we hypothesized opposing behavioral responses of grizzly bears with regard to changes in home-range size. We used the dynamic changes in food resources and population density of grizzly bears as a natural experiment to examine hypotheses regarding these potentially competing influences on grizzly bear home-range size. We found that home-range size did not increase during the period of whitebark pine decline and was not related to proportion of whitebark pine in home ranges. However, female home-range size was negatively associated with an index of population density. Our data indicate that home-range size of grizzly bears in the GYE is not associated with availability of WBP, and, for female grizzly bears, increasing population density may constrain home-range size.

Accrual and drop out in a primary prevention randomised controlled trial: qualitative study.

PubMed

Eborall, Helen C; Stewart, Marlene C W; Cunningham-Burley, Sarah; Price, Jackie F; Fowkes, F Gerry R

2011-01-11

Recruitment and retention of participants are critical to the success of a randomised controlled trial. Gaining the views of potential trial participants who decline to enter a trial and of trial participants who stop the trial treatment is important and can help to improve study processes. Limited research on these issues has been conducted on healthy individuals recruited for prevention trials in the community. Semi-structured interviews with people who were eligible but had declined to participate in the Aspirin for Asymptomatic Atherosclerosis (AAA) trial (N = 11), and AAA trial participants who had stopped taking the trial medication (N = 11). A focus group with further participants who had stopped taking the trial medication (N = 6). (Total participants N = 28). Explanations for declining to participate could be divided into two groups: the first group were characterised by a lack of necessity to participate and a tendency to prioritise other largely mundane problems. The second group's concern was with a high level of perceived risk from participating.Explanations for stopping trial medication fell into four categories: side effects attributed to the trial medication; starting on aspirin or medication contraindicating to aspirin; experiencing an outcome event, and changing one's mind. These results indicate that when planning trials (especially in preventive medicine) particular attention should be given to designing appropriate recruitment materials and processes that fully inform potential recruits of the risks and benefits of participation. ISRCTN66587262.

The perimenopausal aging transition in the female rat brain: decline in bioenergetic systems and synaptic plasticity.

PubMed

Yin, Fei; Yao, Jia; Sancheti, Harsh; Feng, Tao; Melcangi, Roberto C; Morgan, Todd E; Finch, Caleb E; Pike, Christian J; Mack, Wendy J; Cadenas, Enrique; Brinton, Roberta D

2015-07-01

The perimenopause is an aging transition unique to the female that leads to reproductive senescence which can be characterized by multiple neurological symptoms. To better understand potential underlying mechanisms of neurological symptoms of perimenopause, the present study determined genomic, biochemical, brain metabolic, and electrophysiological transformations that occur during this transition using a rat model recapitulating fundamental characteristics of the human perimenopause. Gene expression analyses indicated two distinct aging programs: chronological and endocrine. A critical period emerged during the endocrine transition from regular to irregular cycling characterized by decline in bioenergetic gene expression, confirmed by deficits in fluorodeoxyglucose-positron emission tomography (FDG-PET) brain metabolism, mitochondrial function, and long-term potentiation. Bioinformatic analysis predicted insulin/insulin-like growth factor 1 and adenosine monophosphate-activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (AMPK/PGC1α) signaling pathways as upstream regulators. Onset of acyclicity was accompanied by a rise in genes required for fatty acid metabolism, inflammation, and mitochondrial function. Subsequent chronological aging resulted in decline of genes required for mitochondrial function and β-amyloid degradation. Emergence of glucose hypometabolism and impaired synaptic function in brain provide plausible mechanisms of neurological symptoms of perimenopause and may be predictive of later-life vulnerability to hypometabolic conditions such as Alzheimer's. Copyright © 2015 Elsevier Inc. All rights reserved.

Egg Production in a Coastal Seabird, the Glaucous-Winged Gull (Larus glaucescens), Declines during the Last Century

PubMed Central

Blight, Louise K.

2011-01-01

Seabirds integrate information about oceanic ecosystems across time and space, and are considered sensitive indicators of marine conditions. To assess whether hypothesized long-term foodweb changes such as forage fish declines may be reflected in a consumer's life history traits over time, I used meta-regression to evaluate multi-decadal changes in aspects of egg production in the glaucous-winged gull (Larus glaucescens), a common coastal bird. Study data were derived from literature searches of published papers and unpublished historical accounts, museum egg collections, and modern field studies, with inclusion criteria based on data quality and geographic area of the original study. Combined historical and modern data showed that gull egg size declined at an average of 0.04 cc y−1 from 1902 (108 y), equivalent to a decline of 5% of mean egg volume, while clutch size decreased over 48 y from a mean of 2.82 eggs per clutch in 1962 to 2.25 in 2009. There was a negative relationship between lay date and mean clutch size in a given year, with smaller clutches occurring in years where egg laying commenced later. Lay date itself advanced over time, with commencement of laying presently (2008–2010) 7 d later than in previous studies (1959–1986). This study demonstrates that glaucous-winged gull investment in egg production has declined significantly over the past ∼50–100 y, with such changes potentially contributing to recent population declines. Though gulls are generalist feeders that should readily be able to buffer themselves against food web changes, they are likely nutritionally constrained during the early breeding period, when egg production requirements are ideally met by consumption of high-quality prey such as forage fish. This study's results suggest a possible decline in the availability of such prey, and the incremental long-term impoverishment of a coastal marine ecosystem bordering one of North America's rapidly growing urban areas. PMID:21789207

A complete species census and evidence for regional declines in piping plovers

USGS Publications Warehouse

Haig, Susan M.; Ferland, C.L.; Cuthbert, F.J.; Dingledine, J.; Hecht, A.; McPhillips, N.

2005-01-01

Complete population estimates for widely distributed species are rarely possible. However, for the third time in 10 years, an International Piping Plover (Charadrius melodus) Breeding and Winter Census was conducted throughout the species range in 2001. Nearly 1,400 participants from 32 U.S. states and Puerto Rico; 9 Canadian provinces; St. Pierre and Miquelon, France; Cuba; and the Bahamas visited 2,244 sites covering 11,836 km of shoreline habitat. During the winter census, 2,389 piping plovers were observed at 33.5% of potentially occupied sites (n = 352). Of these, 56.8% had a?? 10 birds present. The breeding census recorded 5,945 adults at 777 of 1,892 sites surveyed. More than 80% of sites with piping plovers present had a?? 10 birds. Results indicated an 8.4% increase from 1991 but only a 0.2% increase since 1996. Regional trends suggest that since 1991, number of breeding birds increased on the Atlantic Coast by 78% (2,920 birds; 12.4% increase since 1996) and by 80% in the Great Lakes (72 birds; 50% increase since 1996). However, plovers declined 15% (2,953 birds; 10% decline since 1996) in Prairie Canada/U.S. northern Great Plains. Subregional trends since 1991 reflect a 32.4% decline in Prairie Canada (972 birds; 42.4% decline since 1996), a 2.5% decline in the U.S. northern Great Plains (1,981 birds; 24% increase since 1996), 5.5% decline in eastern Canada (481 birds; 14% increase since 1996), although a 66.2% increase on the U.S. Atlantic Coast (2,430 birds; 12% since 1996). While numbers were down in much of the U.S. northern Great Plains since 1996, an increase (460%, 1,048 birds; 67.7% increase since 1991) was detected on the Missouri River. Results from 3 complete species census efforts provide essential data for conservation planning and assessment and illustrate the utility of global censuses for species of concern.

Effect of Aging on ERP Components of Cognitive Control

PubMed Central

Kropotov, Juri; Ponomarev, Valery; Tereshchenko, Ekaterina P.; Müller, Andreas; Jäncke, Lutz

2016-01-01

As people age, their performance on tasks requiring cognitive control often declines. Such a decline is frequently explained as either a general or specific decline in cognitive functioning with age. In the context of hypotheses suggesting a general decline, it is often proposed that processing speed generally declines with age. A further hypothesis is that an age-related compensation mechanism is associated with a specific cognitive decline. One prominent theory is the compensation hypothesis, which proposes that deteriorated functions are compensated for by higher performing functions. In this study, we used event-related potentials (ERPs) in the context of a GO/NOGO task to examine the age-related changes observed during cognitive control in a large group of healthy subjects aged between 18 and 84 years. The main question we attempted to answer was whether we could find neurophysiological support for either a general decline in processing speed or a compensation strategy. The subjects performed a relatively demanding cued GO/NOGO task with similar omissions and reaction times across the five age groups. The ERP waves of cognitive control, such as N2, P3cue and CNV, were decomposed into latent components by means of a blind source separation method. Based on this decomposition, it was possible to more precisely delineate the different neurophysiological and psychological processes involved in cognitive control. These data support the processing speed hypothesis because the latencies of all cognitive control ERP components increased with age, by 8 ms per decade for the early components (<200 ms) and by 20 ms per decade for the late components. At the same time, the compensatory hypothesis of aging was also supported, as the amplitudes of the components localized in posterior brain areas decreased with age, while those localized in the prefrontal cortical areas increased with age in order to maintain performance on this simple task at a relatively stable level. PMID:27092074

Exception Points and Body Size Contribute to Gender Disparity in Liver Transplantation.

PubMed

Nephew, Lauren D; Goldberg, David S; Lewis, James D; Abt, Peter; Bryan, Mathew; Forde, Kimberly A

2017-08-01

Women are significantly less likely than men to receive a liver transplant and more likely to die on the waitlist. We investigated potential reasons for these disparities, including match run positioning and organ declines caused by small stature of female recipients. We analyzed data from the United Network of Organ Sharing registry of candidates placed on the waitlist from May 10, 2007, through June 17, 2013. Primary outcomes included ranked in first position on a match run, having an organ declined while in first position, declining an organ while in first position because of size mismatch between donor and recipient (body surface area discordance), and death or becoming too sick for liver transplantation. Among 64,995 patients on the waitlist for liver transplantation, 23.1% of men and 15.6% of women received exception points (P < .001). Women listed without exception points were less likely than men to be ranked first (odds ratio [OR], 0.93; 95% CI, 0.88-0.99). Women who achieved first position were more likely to decline an organ than men (OR, 1.15; 95% CI, 1.06-1.26); this difference was reduced after we accounted for recipient body surface area (OR, 1.08; 95% CI, 0.98-1.19). Women with a single organ decline were more likely than men with a single organ decline to die or become too sick for transplantation (OR, 1.26; 95% CI, 1.12-1.41). The difference was reduced after we accounted for exception points (OR, 1.16; 95% CI, 1.12-1.21) and recipient body surface area (OR, 1.01; 95% CI, 0.96-1.06). In an analysis of data from the United Network of Organ Sharing registry, we found that women when compared with men on the waitlist for liver transplantation are disadvantaged by an imbalance in exception point allocation and organ declines because of small stature. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Factors Associated with Four or More Antenatal Care Visits and Its Decline among Pregnant Women in Tanzania between 1999 and 2010

PubMed Central

Gupta, Shivam; Yamada, Goro; Mpembeni, Rose; Frumence, Gasto; Callaghan-Koru, Jennifer A.; Stevenson, Raz; Brandes, Neal; Baqui, Abdullah H.

2014-01-01

In Tanzania, the coverage of four or more antenatal care (ANC 4) visits among pregnant women has declined over time. We conducted an exploratory analysis to identify factors associated with utilization of ANC 4 and ANC 4 decline among pregnant women over time. We used data from 8035 women who delivered within two years preceding Tanzania Demographic and Health Surveys conducted in 1999, 2004/05 and 2010. Multivariate logistic regression models were used to examine the association between all potential factors and utilization of ANC 4; and decline in ANC 4 over time. Factors positively associated with ANC 4 utilization were higher quality of services, testing and counseling for HIV during ANC, receiving two or more doses of SP (Sulphadoxine Pyrimethamine)/Fansidar for preventing malaria during ANC and higher educational status of the woman. Negatively associated factors were residing in a zone other than Eastern zone, never married woman, reported long distance to health facility, first ANC visit after four months of pregnancy and woman's desire to avoid pregnancy. The factors significantly associated with decline in utilization of ANC 4 were: geographic zone and age of the woman at delivery. Strategies to increase ANC 4 utilization should focus on improvement in quality of care, geographic accessibility, early ANC initiation, and services that allow women to avoid pregnancy. The interconnected nature of the Tanzanian Health System is reflected in ANC 4 decline over time where introduction of new programs might have had unintended effects on existing programs. An in-depth assessment of the recent policy change towards Focused Antenatal Care and its implementation across different geographic zones, including its effect on the perception and understanding among women and performance and counseling by health providers can help explain the decline in ANC 4. PMID:25036291

Quantitative assessment of a data-limited recreational bonefish fishery using a time-series of fishing guides reports.

PubMed

Santos, Rolando O; Rehage, Jennifer S; Adams, Aaron J; Black, Brooke D; Osborne, Jason; Kroloff, Emily K N

2017-01-01

Recreational fisheries can be prone to severe declines, yet these fisheries, particularly catch-and-release, are often data-limited, constraining our ability to conduct stock assessments. A combination of catch and effort indices derived from fisheries-dependent data (FDD) gathered from fishing logbooks could be a powerful approach to inform these data gaps. This study demonstrates the utility of using different catch metrics such as indices of abundance, species richness associated with reported catch, and the success rate of targeted trips, to assess historical shifts in the trajectory of the data-limited bonefish (Albula vulpes) fishery in Florida Bay, an economically-important recreational fishery within the Caribbean Basin. We used FDD from fishing guide reports submitted to Everglades National Park to determine temporal patterns in the bonefish population over the past 35 years. These reports indicated a decline in recreational catches in Florida Bay since the late 1980s, with an accelerated decline starting in the late 1990s-early 2000s. Analyses showed an overall 42% reduction in bonefish catches. Trends in the proportion of positive trips (i.e., the probability of catching success) followed the declining catch patterns, suggesting major population changes starting in 1999-2000. As bonefish catches declined, species richness in bonefish trips increased by 34%, suggesting a decrease in bonefish abundance and/or shift in fishing effort (e.g., giving-up time, changes in preferred species). Results provide additional resolution to a pattern of decline for bonefish in South Florida and highlight the value of reconstructing time-series for the development of hypotheses about the potential driving mechanisms of species decline. Further, the data-limited nature of most recreational fisheries, and the increase in a use of catch-and-release as a fisheries management strategy point to the need to develop further data integration tools to assess population trends and the sustainability of these fishery resources.

Factors associated with four or more antenatal care visits and its decline among pregnant women in Tanzania between 1999 and 2010.

PubMed

Gupta, Shivam; Yamada, Goro; Mpembeni, Rose; Frumence, Gasto; Callaghan-Koru, Jennifer A; Stevenson, Raz; Brandes, Neal; Baqui, Abdullah H

2014-01-01

In Tanzania, the coverage of four or more antenatal care (ANC 4) visits among pregnant women has declined over time. We conducted an exploratory analysis to identify factors associated with utilization of ANC 4 and ANC 4 decline among pregnant women over time. We used data from 8035 women who delivered within two years preceding Tanzania Demographic and Health Surveys conducted in 1999, 2004/05 and 2010. Multivariate logistic regression models were used to examine the association between all potential factors and utilization of ANC 4; and decline in ANC 4 over time. Factors positively associated with ANC 4 utilization were higher quality of services, testing and counseling for HIV during ANC, receiving two or more doses of SP (Sulphadoxine Pyrimethamine)/Fansidar for preventing malaria during ANC and higher educational status of the woman. Negatively associated factors were residing in a zone other than Eastern zone, never married woman, reported long distance to health facility, first ANC visit after four months of pregnancy and woman's desire to avoid pregnancy. The factors significantly associated with decline in utilization of ANC 4 were: geographic zone and age of the woman at delivery. Strategies to increase ANC 4 utilization should focus on improvement in quality of care, geographic accessibility, early ANC initiation, and services that allow women to avoid pregnancy. The interconnected nature of the Tanzanian Health System is reflected in ANC 4 decline over time where introduction of new programs might have had unintended effects on existing programs. An in-depth assessment of the recent policy change towards Focused Antenatal Care and its implementation across different geographic zones, including its effect on the perception and understanding among women and performance and counseling by health providers can help explain the decline in ANC 4.

Decline in Physical Function and Risk for Elder Abuse Reported to Social Services in a Community-Dwelling Population of Older Adults

PubMed Central

Dong, XinQi; Simon, Melissa; Evans, Denis

2012-01-01

Objectives Elder abuse is an important public health and human rights issue and is associated with increased morbidity and mortality. This study aimed to examine the longitudinal association between decline in physical function and the risk for elder abuse. Design Prospective population-based study Setting Geographically defined community in Chicago. Participants Chicago Health and Aging Project (CHAP) is a population-based study (N=6,159), and we identified 143 CHAP participants who had elder abuse reported to social services agency from 1993–2010. Participants The primary independent variable was objectively assessed physical function using decline in physical performance testing (Tandem stand, measured walk and chair stand). Secondary independent variables were assessed using the decline in self-reported Katz, Nagi, and Rosow-Breslau scales. Outcomes were reported and confirmed elder abuse and specific subtypes of elder abuse (physical, psychological, caregiver neglect and financial exploitation). Logistic regression models were used to assess the association of decline in physical function measures and risk for elder abuse. Results After adjusting for potential confounders, every 1 point decline in physical performance testing (OR, 1.13(1.06–1.19)), Katz impairment (OR, 1.29(1.15–1.45)), Nagi impairment (OR, 1.30(1.13–1.49)) and Rosow Breslau impairment (OR, 1.42(1.15–1.74)) were associated with increased risk for elder abuse. Lowest tertiles of physical performance testing (OR, 4.92 (1.39–17.46), highest tertiles of Katz impairment (OR, 3.99 (2.18–7.31), Nagi impairment (OR, 2.37 (1.08–5.23), and Rosow Breslau impairment (2.85 (1.39–5.84) were associated with increased risk for elder abuse. Conclusion Decline in objectively assessed physical function and self-reported physical function are associated with increased risk for elder abuse. PMID:23002901

Targeting Functional Decline in Alzheimer Disease: A Randomized Trial.

PubMed

Callahan, Christopher M; Boustani, Malaz A; Schmid, Arlene A; LaMantia, Michael A; Austrom, Mary G; Miller, Douglas K; Gao, Sujuan; Ferguson, Denisha Y; Lane, Kathleen A; Hendrie, Hugh C

2017-02-07

Alzheimer disease results in progressive functional decline, leading to loss of independence. To determine whether collaborative care plus 2 years of home-based occupational therapy delays functional decline. Randomized, controlled clinical trial. (ClinicalTrials.gov: NCT01314950). Urban public health system. 180 community-dwelling participants with Alzheimer disease and their informal caregivers. All participants received collaborative care for dementia. Patients in the intervention group also received in-home occupational therapy delivered in 24 sessions over 2 years. The primary outcome measure was the Alzheimer's Disease Cooperative Study Group Activities of Daily Living Scale (ADCS ADL); performance-based measures included the Short Physical Performance Battery (SPPB) and Short Portable Sarcopenia Measure (SPSM). At baseline, clinical characteristics did not differ significantly between groups; the mean Mini-Mental State Examination score for both groups was 19 (SD, 7). The intervention group received a median of 18 home visits from the study occupational therapists. In both groups, ADCS ADL scores declined over 24 months. At the primary end point of 24 months, ADCS ADL scores did not differ between groups (mean difference, 2.34 [95% CI, -5.27 to 9.96]). We also could not definitively demonstrate between-group differences in mean SPPB or SPSM values. The results of this trial are indeterminate and do not rule out potential clinically important effects of the intervention. The authors could not definitively demonstrate whether the addition of 2 years of in-home occupational therapy to a collaborative care management model slowed the rate of functional decline among persons with Alzheimer disease. This trial underscores the burden undertaken by caregivers as they provide care for family members with Alzheimer disease and the difficulty in slowing functional decline. National Institute on Aging.

The relationship of bilingualism to cognitive decline: The Australian Longitudinal Study of Ageing.

PubMed

Mukadam, Naaheed; Jichi, Fatima; Green, David; Livingston, Gill

2018-02-01

We wished to clarify the link between bilingualism and cognitive decline, and examine whether improved executive function due to bilingualism may be a factor in preventing cognitive decline. We used the Australian Longitudinal Study of Ageing which collected data on 2087 participants aged over 65 over 20 years. We compared baseline demographics, health, and social characteristics between bilingual and non-bilingual participants. We used linear mixed models analysis to explore the effect of bilingualism on MMSE score over time and linear regression to explore the effect of bilingualism on baseline MMSE scores, controlling for pre-specified potential confounders. Bilingual participants had lower baseline MMSE scores than the non-bilingual population (mean difference = -2.3 points; 95% confidence intervals = 1.56-2.90). This was fully explained by education and National Adult Reading Test scores (17.4; standard deviation [SD] =7.7 versus 28.1; SD = 8.2) which also partly explained baseline executive function test scores differences. Bilingual and non-bilingual participants did not differ in MMSE decline over time (-0.33 points, P = 0.31) nor on baseline tests of executive function (-0.26, P = 0.051). In this cohort, education rather than bilingualism was a predictor of MMSE score, and being bilingual did not protect from cognitive decline. We conclude that bilingualism is complex, and when it is not the result of greater educational attainment, it does not always protect from cognitive decline. Neuroprotective effects of bilingualism over time may be attributable to the precise patterns of language use but not to bilingualism per se. Copyright © 2017 John Wiley & Sons, Ltd.

Association between Late-Life Social Activity and Motor Decline in Older Adults

PubMed Central

Buchman, Aron S.; Boyle, Patricia A.; Wilson, Robert S.; Fleischman, Debra A.; Leurgans, Sue; Bennett, David A.

2009-01-01

Background Loss of motor function is a common consequence of aging, but little is known about factors that predict idiopathic motor decline. Methods We studied 906 persons without dementia, history of stroke or Parkinson's disease participating in the Rush Memory and Aging Project. At baseline, they rated their frequency of participation in common social activities. Outcome was annual change in global motor function, based on nine measures of muscle strength and nine motor performances. Results Mean social activity score at baseline was 2.6 (SD=0.58), with higher scores indicating more frequent participation in social activities. In a generalized estimating equation model, controlling for age, sex and education, motor function declined by about 0.05 unit/year [Estimate, 0.016; 95%CI (-0.057, -0.041); p=0.017]. Each 1-point decrease in social activity was associated with about a 33% more rapid rate of decline in motor function [Estimate, 0.016; 95%CI (0.003, 0.029); p=0.017)]. This amount of annual motor decline was associated with a more than 40% increased risk of death (Hazard Ratio: 1.44; 95%CI: 1.30, 1.60) and 65% increased risk of incident Katz disability (Hazard Ratio: 1.65; 95%CI: 1.48, 1.83). The association of social activity with change in motor function did not vary along demographic lines and was unchanged after controlling for potential confounders including late-life physical and cognitive activity, disability, global cognition, depressive symptoms, body composition and chronic medical conditions [Estimate, 0.025; 95%CI (0.005, 0.045); p=0.010]. Conclusion Less frequent participation in social activities is associated with a more rapid rate of motor decline in old age. PMID:19546415

Impaired Sleep Predicts Cognitive Decline in Old People: Findings from the Prospective KORA Age Study.

PubMed

Johar, Hamimatunnisa; Kawan, Rasmila; Emeny, Rebecca Thwing; Ladwig, Karl-Heinz

2016-01-01

To investigate the association between sleep-related characteristics and cognitive change over 3 years of follow up in an aged population. Sleep characteristics and covariates were assessed at baseline in a standardized interview and clinical examination of the population-based KORA Age Study (n = 740, mean age = 75 years). Cognitive score (determined by telephone interview for cognitive status, TICS-m) was recorded at baseline and 3 years later. At baseline, 82.83% (n = 613) of participants had normal cognitive status, 13.51% (n = 100) were classified with mild cognitive impairment (MCI), and 3.64% (n = 27) with probable dementia. The effect of three distinct patterns of poor sleep (difficulties initiating [DIS] or maintaining sleep [DMS], daytime sleepiness [DS] or sleep duration) were considered on a change in cognitive score with adjustments for potential confounders in generalized linear regression models. Cognitive decline was more pronounced in individuals with DMS compared to those with no DMS (β = 1.33, 95% CI = 0.41-2.24, P < 0.001). However, the predictive power of DMS was only significant in individuals with normal cognition and not impaired subjects at baseline. Prolonged sleep duration increased the risk for cognitive decline in cognitively impaired elderly (β = 1.86, 95% CI = 0.15-3.57, P = 0.03). Other sleep characteristics (DIS and DS) were not significantly associated with cognitive decline. DMS and long sleep duration were associated with cognitive decline in normal and cognitively impaired elderly, respectively. The identification of impaired sleep quality may offer intervention strategies to deter cognitive decline in the elderly with normal cognitive function. © 2016 Associated Professional Sleep Societies, LLC.

Reservoir-host amplification of disease impact in an endangered amphibian.

PubMed

Scheele, Ben C; Hunter, David A; Brannelly, Laura A; Skerratt, Lee F; Driscoll, Don A

2017-06-01

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts-species that carry infection while maintaining high abundance but are rarely killed by disease-can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined amphibian species. © 2016 Society for Conservation Biology.

Projecting avian response to linked changes in groundwater and riparian floodplain vegetation along a dryland river: A scenario analysis

USGS Publications Warehouse

Arriana, Brand L.; Stromberg, J.C.; Goodrich, D.C.; Dixon, M.D.; Lansey, K.; Kang, D.; Brookshire, D.S.; Cerasale, D.J.

2011-01-01

Groundwater is a key driver of riparian condition on dryland rivers but is in high demand for municipal, industrial, and agricultural uses. Approaches are needed to guide decisions that balance human water needs while conserving riparian ecosystems. We developed a space-for-time substitution model that links groundwater change scenarios implemented within a Decision Support System (DSS) with proportions of floodplain vegetation types and abundances of breeding and migratory birds along the upper San Pedro River, AZ, USA. We investigated nine scenarios ranging from groundwater depletion to recharge. In groundwater decline scenarios, relative proportions of tall-canopied obligate phreatophytes (Populus/Salix, cottonwood/willow) on the floodplain progressively decline, and shrubbier species less dependent on permanent water sources (e.g. Tamarix spp., saltcedar) increase. These scenarios result in broad shifts in the composition of the breeding bird community, with canopy-nesting and water-obligate birds declining but midstory nesting birds increasing in abundance as groundwater declines. For the most extreme draw-down scenario where all reaches undergo groundwater declines, models project that only 10% of the upper San Pedro floodplain would be comprised of cottonwood/willow (73% saltcedar and 18% mesquite), and abundances of canopy-nesting, water-obligate, and spring migrant birds would decline 48%, 72%, and 40%, respectively. Groundwater recharge scenarios were associated with increases in canopy-nesting birds particularly given the extreme recharge scenario (all reaches regain shallow water tables and perennial streamflow). Model outputs serve to assess the sensitivity of biotic groups to potential changes in groundwater and thus to rank scenarios based on their expected ecological impacts. ?? 2010 John Wiley & Sons, Ltd.

Social relationships and cognitive decline: a systematic review and meta-analysis of longitudinal cohort studies.

PubMed

Kuiper, Jisca S; Zuidersma, Marij; Zuidema, Sytse U; Burgerhof, Johannes Gm; Stolk, Ronald P; Oude Voshaar, Richard C; Smidt, Nynke

2016-08-01

Although poor social relationships are assumed to contribute to cognitive decline, meta-analytic approaches have not been applied. Individual study results are mixed and difficult to interpret due to heterogeneity in measures of social relationships. We conducted a systematic review and meta-analysis to investigate the relation between poor social relationships and cognitive decline. MEDLINE, Embase and PsycINFO were searched for longitudinal cohort studies examining various aspects of social relationships and cognitive decline in the general population. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using random effects meta-analysis. Sources of heterogeneity were explored and likelihood of publication bias was assessed. We stratified analyses according to three aspects of social relationships: structural, functional and a combination of these. We identified 43 articles. Poor social relationships predicted cognitive decline; for structural (19 studies): pooled OR: 1.08 (95% CI: 1.05-1.11); functional (8 studies): pooled OR: 1.15 (95% CI: 1.00-1.32); and combined measures (7 studies): pooled OR: 1.12 (95% CI: 1.01-1.24). Meta-regression and subgroup analyses showed that the heterogeneity could be explained by the type of social relationship measurement and methodological quality of included studies. Despite heterogeneity in study design and measures, our meta-analyses show that multiple aspects of social relationships are associated with cognitive decline. As evidence for publication bias was found, the association might be overestimated and should therefore be interpreted with caution. Future studies are needed to better define the mechanisms underlying these associations. Potential causality of this prognostic association should be examined in future randomized controlled studies. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Self-Reported Decline in Everyday Function, Cognitive Symptoms, and Cognitive Function in People With HIV.

PubMed

Laverick, Rosanna; Haddow, Lewis; Daskalopoulou, Marina; Lampe, Fiona; Gilson, Richard; Speakman, Andrew; Antinori, Andrea; Bruun, Tina; Vassilenko, Anna; Collins, Simon; Rodger, Alison

2017-11-01

We determined factors associated with self-reported decline in activities of daily living (ADLs) and symptoms of cognitive impairment in HIV positive adults in 5 European clinics. HIV+ adults underwent computerized and pen-and-paper neuropsychological tests and questionnaires of cognitive symptoms and ADLs. We considered cognitive function in 5 domains, psychosocial factors, and clinical parameters as potentially associated with symptoms. Separate regression analyses were used to determine factors associated with a decline in ADL (defined as self-reported decline affecting ≥2 ADLs and attributed to cognitive difficulties) and self-reported frequency of symptoms of cognitive impairment. We also estimated the diagnostic accuracy of both questionnaires as tests for cognitive impairment. Four hundred forty-eight patients completed the assessments [mean age 45.8 years, 84% male, 87% white, median CD4 count 550 cells/mm, median time since HIV diagnosis 9.9 years, 81% virologically suppressed (HIV-1 plasma RNA <50 copies/mL)]. Ninety-six (21.4%) reported decline in ADLs and attributed this to cognitive difficulties. Self-reported decline in ADLs and increased symptoms of cognitive impairment were both associated with worse performance on some cognitive tests. There were also strong associations with financial difficulties, depressive and anxiety symptoms, unemployment, and longer time since HIV diagnosis. Both questionnaires performed poorly as diagnostic tests for cognitive impairment. Patients' own assessments of everyday function and symptoms were associated with objectively measured cognitive function. However, there were strong associations with other psychosocial issues including mood and anxiety disorders and socioeconomic hardship. This should be considered when assessing HIV-associated cognitive impairment in clinical care or research studies.

Declining populations of the fingernail clam Musculium transversum in the upper Mississippi River

USGS Publications Warehouse

Wilson, D.M.; Naimo, T.J.; Weiner, J.G.; Anderson, R.V.; Sandheinrich, M.B.; Sparks, Richard E.

1995-01-01

We examined recent temporal trends in the abundance of fingernail clams Musculium transversum (formerly Sphaerium transversum) in the upper Mississippi River. Historical data on densities of fingernail clams were obtained from regional scientists and published literature. We also sampled benthos in six navigation pools in summer 1991, finding very few fingernail clams. The combined data set, including historical data and sampling results, extended from 1973 to 1992 and was sufficient to statistically evaluate trends in densities of fingernail clams in eight pools. Populations of fingernail clams declined significantly in five of the eight pools examined (Pools 2, 5, 7, 9, and 19), which spanned a 700-km reach of river from St. Paul, Minnesota, to Keokuk, Iowa. Densities in Pool 19, which had the longest historical record on fingernail clam abundance, averaged 30 000 m super(-2) in 1985 and progressively declined to zero in 1990. Combined data from all eight pools showed a significant decline in abundance of fingernail clams. An evaluation of potential causal factors led us to hypothesize that the population declines in Pools 2 to 9 were linked to point-source pollution rather than to dredging activity or commercial navigation traffic. In Pool 19, the declines of fingernail clams may have resulted from low-flow conditions during drought periods, but the causal mechanisms by which low flow influences fingernail clam abundance are unclear. The decrease in fingernail clam populations may adversely affect certain fish and wildlife, such as migrating lesser scaup Aythya affinis, which feed heavily on the small mollusk. Moreover, the decreases in populations of this pollution-sensitive mollusk may signal a large-scale deterioration in the health of this riverine ecosystem.

Habitat Fragmentation and Species Extirpation in Freshwater Ecosystems; Causes of Range Decline of the Indus River Dolphin (Platanista gangetica minor)

PubMed Central

Braulik, Gill T.; Arshad, Masood; Noureen, Uzma; Northridge, Simon P.

2014-01-01

Habitat fragmentation of freshwater ecosystems is increasing rapidly, however the understanding of extinction debt and species decline in riverine habitat fragments lags behind that in other ecosystems. The mighty rivers that drain the Himalaya - the Ganges, Brahmaputra, Indus, Mekong and Yangtze - are amongst the world’s most biodiverse freshwater ecosystems. Many hundreds of dams have been constructed, are under construction, or are planned on these rivers and large hydrological changes and losses of biodiversity have occurred and are expected to continue. This study examines the causes of range decline of the Indus dolphin, which inhabits one of the world’s most modified rivers, to demonstrate how we may expect other vertebrate populations to respond as planned dams and water developments come into operation. The historical range of the Indus dolphin has been fragmented into 17 river sections by diversion dams; dolphin sighting and interview surveys show that river dolphins have been extirpated from ten river sections, they persist in 6, and are of unknown status in one section. Seven potential factors influencing the temporal and spatial pattern of decline were considered in three regression model sets. Low dry-season river discharge, due to water abstraction at irrigation barrages, was the principal factor that explained the dolphin’s range decline, influencing 1) the spatial pattern of persistence, 2) the temporal pattern of subpopulation extirpation, and 3) the speed of extirpation after habitat fragmentation. Dolphins were more likely to persist in the core of the former range because water diversions are concentrated near the range periphery. Habitat fragmentation and degradation of the habitat were inextricably intertwined and in combination caused the catastrophic decline of the Indus dolphin. PMID:25029270

Does left ventricular hypertrophy affect cognition and brain structural integrity in type 2 diabetes? Study design and rationale of the Diabetes and Dementia (D2) study.

PubMed

Patel, Sheila K; Restrepo, Carolina; Werden, Emilio; Churilov, Leonid; Ekinci, Elif I; Srivastava, Piyush M; Ramchand, Jay; Wai, Bryan; Chambers, Brian; O'Callaghan, Christopher J; Darby, David; Hachinski, Vladimir; Cumming, Toby; Donnan, Geoff; Burrell, Louise M; Brodtmann, Amy

2017-04-07

Cognitive impairment is common in type 2 diabetes mellitus, and there is a strong association between type 2 diabetes and Alzheimer's disease. However, we do not know which type 2 diabetes patients will dement or which biomarkers predict cognitive decline. Left ventricular hypertrophy (LVH) is potentially such a marker. LVH is highly prevalent in type 2 diabetes and is a strong, independent predictor of cardiovascular events. To date, no studies have investigated the association between LVH and cognitive decline in type 2 diabetes. The Diabetes and Dementia (D2) study is designed to establish whether patients with type 2 diabetes and LVH have increased rates of brain atrophy and cognitive decline. The D2 study is a single centre, observational, longitudinal case control study that will follow 168 adult patients aged >50 years with type 2 diabetes: 50% with LVH (case) and 50% without LVH (control). It will assess change in cardiovascular risk, brain imaging and neuropsychological testing between two time-points, baseline (0 months) and 24 months. The primary outcome is brain volume change at 24 months. The co-primary outcome is the presence of cognitive decline at 24 months. The secondary outcome is change in left ventricular mass associated with brain atrophy and cognitive decline at 24 months. The D2 study will test the hypothesis that patients with type 2 diabetes and LVH will exhibit greater brain atrophy than those without LVH. An understanding of whether LVH contributes to cognitive decline, and in which patients, will allow us to identify patients at particular risk. Australian New Zealand Clinical Trials Registry ( ACTRN12616000546459 ), date registered, 28/04/2016.

Targeting Functional Decline: Results from the Alzheimer’s Disease Multiple Intervention Trial

PubMed Central

Callahan, Christopher M.; Boustani, Malaz A.; Schmid, Arlene A.; LaMantia, Michael A.; Austrom, Mary G.; Miller, Douglas K.; Gao, Sujuan; Ferguson, Denisha Y.; Lane, Kathleen A.; Hendrie, Hugh C.

2017-01-01

Background Alzheimer’s disease (AD) results in progressive functional decline leading to loss of independence Objective To determine whether collaborative care plus two years of home-based occupational therapy delays functional decline Design Randomized controlled clinical trial Setting Urban public health system Patients 180 community-dwelling subjects who were diagnosed with AD and their informal caregivers Interventions All subjects received collaborative care for dementia. Intervention patients also received in-home occupational therapy delivered in 24 sessions over 2 years. Measurements The primary outcome measures was the Alzheimer’s Disease Cooperative Studies Group Activities of Daily Living Scale (ADCS ADL); performance based measures included the Short Physical Performance Battery (SPPB) and Short Portable Sarcopenia Measure (SPSM) Results At baseline, there were no significant between group differences in clinical characteristics; the mean MMSE for both groups was 19 (SD=7). The intervention group received a median of 18 home visits from the study occupational therapists. Both groups declined in ADCS ADL scores over 24 months. At the primary endpoint of 24 months, there were no between group differences in ADCS ADL scores (mean difference 2.34, 95% CI −5.27, 9.96). We were also unable to definitively demonstrate between-group differences in the mean SPPB or SPSM. Limitations The results of this trial are indeterminate and do not rule out potentially clinically important effects of the intervention. Conclusions We were unable to definitively demonstrate whether the addition of two years of in-home occupational therapy to a collaborative care management model slows the rate of functional decline among persons with AD. This trial underscores the burden undertaken by family caregivers as they provide care for persons with AD and the difficulty in slowing functional decline. PMID:27893087

Cognition and Depression Following Deep Brain Stimulation of the Subthalamic Nucleus and Globus Pallidus Pars Internus in Parkinson's Disease: A Meta-Analysis.

PubMed

Combs, Hannah L; Folley, Bradley S; Berry, David T R; Segerstrom, Suzanne C; Han, Dong Y; Anderson-Mooney, Amelia J; Walls, Brittany D; van Horne, Craig

2015-12-01

Parkinson's disease (PD) is a common, degenerative disorder of the central nervous system. Individuals experience predominantly extrapyramidal symptoms including resting tremor, rigidity, bradykinesia, gait abnormalities, cognitive impairment, depression, and neurobehavioral concerns. Cognitive impairments associated with PD are diverse, including difficulty with attention, processing speed, executive functioning, memory recall, visuospatial functions, word-retrieval, and naming. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus internus (GPi) is FDA approved and has been shown to be effective in reducing motor symptoms of PD. Studies have found that stimulating STN and GPi are equally effective at improving motor symptoms and dyskinesias; however, there has been discrepancy as to whether the cognitive, behavioral, and mood symptoms are affected differently between the two targets. The present study used random-effects meta-analytic models along with a novel p-curve analytic procedure to compare the potential cognitive and emotional impairments associated with STN-DBS in the current literature to those associated with GPi-DBS. Forty-one articles were reviewed with an aggregated sample size of 1622 patients. Following STN-DBS, small declines were found in psychomotor speed, memory, attention, executive functions, and overall cognition; and moderate declines were found in both semantic and phonemic fluency. However, GPi-DBS resulted in fewer neurocognitive declines than STN-DBS (small declines in attention and small-moderate declines in verbal fluency). With regards to its effect on depression symptomatology, both GPi-DBS and STN-DBS resulted in lower levels of depressive symptoms post-surgery. From a neurocognitive standpoint, both GPi-DBS and STN-DBS produce subtle cognitive declines but appears to be relatively well tolerated.

Habitat fragmentation and species extirpation in freshwater ecosystems; causes of range decline of the Indus river dolphin (Platanista gangetica minor).

PubMed

Braulik, Gill T; Arshad, Masood; Noureen, Uzma; Northridge, Simon P

2014-01-01

Habitat fragmentation of freshwater ecosystems is increasing rapidly, however the understanding of extinction debt and species decline in riverine habitat fragments lags behind that in other ecosystems. The mighty rivers that drain the Himalaya - the Ganges, Brahmaputra, Indus, Mekong and Yangtze - are amongst the world's most biodiverse freshwater ecosystems. Many hundreds of dams have been constructed, are under construction, or are planned on these rivers and large hydrological changes and losses of biodiversity have occurred and are expected to continue. This study examines the causes of range decline of the Indus dolphin, which inhabits one of the world's most modified rivers, to demonstrate how we may expect other vertebrate populations to respond as planned dams and water developments come into operation. The historical range of the Indus dolphin has been fragmented into 17 river sections by diversion dams; dolphin sighting and interview surveys show that river dolphins have been extirpated from ten river sections, they persist in 6, and are of unknown status in one section. Seven potential factors influencing the temporal and spatial pattern of decline were considered in three regression model sets. Low dry-season river discharge, due to water abstraction at irrigation barrages, was the principal factor that explained the dolphin's range decline, influencing 1) the spatial pattern of persistence, 2) the temporal pattern of subpopulation extirpation, and 3) the speed of extirpation after habitat fragmentation. Dolphins were more likely to persist in the core of the former range because water diversions are concentrated near the range periphery. Habitat fragmentation and degradation of the habitat were inextricably intertwined and in combination caused the catastrophic decline of the Indus dolphin.

Fasting Insulin Levels and Cognitive Decline in Older Women without Diabetes

PubMed Central

van Oijen, Marieke; Okereke, Olivia I.; Kang, Jae Hee; Pollak, Michael N.; Hu, Frank B.; Hankinson, Susan E.; Grodstein, Francine

2008-01-01

Background Type 2 diabetes has been associated with an increased risk of dementia. To assess possible independent effects of insulin, we investigated the relation of insulin levels to cognitive decline in nondiabetic women. Methods Fasting plasma insulin levels were measured in mid-life in 1,416 nondiabetic Nurses’ Health Study participants, who also completed cognitive testing that began 10 years later (current age: 70–75 years). Over 4 years, 3 assessments of general cognition, verbal memory, category fluency and attention were administered. Primary outcomes were the Telephone Interview for Cognitive Status (TICS) performance, the global score (average of all tests) and verbal memory (average of verbal recall tests). Linear mixed-effects models were used to calculate the association between insulin and cognitive decline. Results Higher insulin levels were associated with a faster decline on the TICS and verbal memory. For analysis, batch-specific quartiles of insulin levels were constructed. Compared to the lowest quartile, adjusted differences in the annual rates of decline (with 95% CI values in parentheses) for the second, third and fourth quartiles were: TICS, −0.06 (−0.16, 0.03), −0.14 (−0.24, −0.04), and −0.09 (−0.19, 0.01) points (p trend = 0.04); verbal memory, −0.01 (−0.04, 0.02), −0.05 (−0.08, −0.02), and −0.02 (−0.05, 0.01) units (p trend = 0.02). These associations remained after multivariable adjustment. Conclusions Our study provides evidence for a potential role of higher fasting insulin levels in cognitive decline, possibly independent of diabetes. PMID:18421217

Assessment of Vegetation Responses and Sensitivity to the Millennium Drought in Australia

NASA Astrophysics Data System (ADS)

Jiao, T.; Williams, C. A.

2016-12-01

During the period from 1997 to 2009, Australia experienced one of the most severe and persistent drought known as the Millennium Drought (MD). Major water shortages were reported across the Australian continent as well as a great many tree mortality during and post this drought event. Given the projection of hotter and drier conditions for much of the continent, it is critical to analyze the impacts of climate extremes like MD as an indicator of possible impacts of future trends. Despite many field investigation, large-area monitoring of vegetation decline from MD remains lacking. Here, multi-source remote sensing datasets and novel methods were employed to assess the impacts of MD on vegetation in Australia in terms of the magnitude and sensitivity. Vegetation variables examined include fraction of photosynthetically absorbed radiation (fPar), vegetation optical depth (VOD) and aboveground biomass (AGB). Drought indicators are calculated based on precipitation and potential evapotranspiration from meteorological data. We found consistent spatial patterns in drought-induced declines among fPar, VOD and AGB. Common declines were observed in the east of New South Wales (NSW), the southeast of Queensland, the center and east of Victoria, and Tasmania. Severe declines (>0.2) in fPar concentrate in open forests and shrub lands while regions with more than 0.1 of decline in VOD are found widely across biome types. The net decrease in AGB could reach more than 20 Mg C per ha in the west of Victoria and the southwest of NSW. Sensitivity analysis shows that forests followed by herbaceous are more sensitive to drought than shrubs in terms of declines in fPar and VOD. In addition, vegetation tends to have larger sensitivity in semi-arid or semi-mesic regions than in areas that are either too dry or too wet.

Hemoglobin Decline in Children with Chronic Kidney Disease: Baseline Results from the Chronic Kidney Disease in Children Prospective Cohort Study

PubMed Central

Fadrowski, Jeffrey J.; Pierce, Christopher B.; Cole, Stephen R.; Moxey-Mims, Marva; Warady, Bradley A.; Furth, Susan L.

2008-01-01

Background and objectives: The level of glomerular filtration rate at which hemoglobin declines in chronic kidney disease is poorly described in the pediatric population. Design, setting, participants, & measurements: This cross-sectional study of North American children with chronic kidney disease examined the association of glomerular filtration rate, determined by the plasma disappearance of iohexol, and hemoglobin concentration. Results: Of the 340 patients studied, the mean age was 11 ± 4 yr, the mean glomerular filtration rate was 42 ± 14 ml/min per 1.73 m2, and the mean hemoglobin was 12.5 ± 1.5. Below a glomerular filtration rate of 43, the hemoglobin declined by 0.3 g/dl (95% confidence interval −0.2 to −0.5) for every 5-ml/min per 1.73 m2 decrease in glomerular filtration rate. Above a glomerular filtration rate of 43 ml/min per 1.73 m2, the hemoglobin showed a nonsignificant decline of 0.1 g/dl for every 5-ml/min per 1.73 m2 decrease in glomerular filtration rate. Conclusions: In pediatric patients with chronic kidney disease, hemoglobin declines as an iohexol-determined glomerular filtration rate decreases below 43 ml/min per 1.73 m2. Because serum creatinine–based estimated glomerular filtration rates may overestimate measured glomerular filtration rate in this population, clinicians need to be mindful of the potential for hemoglobin decline and anemia even at early stages of chronic kidney disease, as determined by current Schwartz formula estimates. Future longitudinal analyses will further characterize the relationship between glomerular filtration rate and hemoglobin, including elucidation of reasons for the heterogeneity of this association among individuals. PMID:18235140

Integrated multi-omic analysis of host-microbiota interactions in acute oak decline.

PubMed

Broberg, Martin; Doonan, James; Mundt, Filip; Denman, Sandra; McDonald, James E

2018-01-30

Britain's native oak species are currently under threat from acute oak decline (AOD), a decline-disease where stem bleeds overlying necrotic lesions in the inner bark and larval galleries of the bark-boring beetle, Agrilus biguttatus, represent the primary symptoms. It is known that complex interactions between the plant host and its microbiome, i.e. the holobiont, significantly influence the health status of the plant. In AOD, necrotic lesions are caused by a microbiome shift to a pathobiome consisting predominantly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana and potentially other bacteria. However, the specific mechanistic processes of the microbiota causing tissue necrosis, and the host response, have not been established and represent a barrier to understanding and managing this decline. We profiled the metagenome, metatranscriptome and metaproteome of inner bark tissue from AOD symptomatic and non-symptomatic trees to characterise microbiota-host interactions. Active bacterial virulence factors such as plant cell wall-degrading enzymes, reactive oxygen species defence and flagella in AOD lesions, along with host defence responses including reactive oxygen species, cell wall modification and defence regulators were identified. B. goodwinii dominated the lesion microbiome, with significant expression of virulence factors such as the phytopathogen effector avrE. A smaller proportion of microbiome activity was attributed to G. quercinecans and R. victoriana. In addition, we describe for the first time the potential role of two previously uncharacterised Gram-positive bacteria predicted from metagenomic binning and identified as active in the AOD lesion metatranscriptome and metaproteome, implicating them in lesion formation. This multi-omic study provides novel functional insights into microbiota-host interactions in AOD, a complex arboreal decline disease where polymicrobial-host interactions result in lesion formation on tree stems. We present the first descriptions of holobiont function in oak health and disease, specifically, the relative lesion activity of B. goodwinii, G. quercinecans, Rahnella victoriana and other bacteria. Thus, the research presented here provides evidence of some of the mechanisms used by members of the lesion microbiome and a template for future multi-omic research into holobiont characterisation, plant polymicrobial diseases and pathogen defence in trees.

Epidemic Potential of Measles and Rubella.

ERIC Educational Resources Information Center

Hinman, Alan R.; Preblud, Stephen R.

1980-01-01

Improvements in immunization levels and declines in disease incidence have been brought about effectively by the enactment and enforcement of immunization requirements for school-age children and military recruits. Colleges and universities should also institute immunization requirements as a condition of enrollment. (Authors/CJ)

Improving organ donation rates by modifying the family approach process.

PubMed

Ebadat, Aileen; Brown, Carlos V R; Ali, Sadia; Guitierrez, Tim; Elliot, Eric; Dworaczyk, Sarah; Kadric, Carie; Coopwood, Ben

2014-06-01

The purpose of this study was to identify steps during family approach for organ donation that may be modified to improve consent rates of potential organ donors. Retrospective study of our local organ procurement organization (OPO) database of potential organ donors. Modifiable variables involved in the family approach of potential organ donors were collected and included race and sex of OPO representative, individual initiating approach discussion with family (RN or MD vs. OPO), length of donation discussion, use of a translator, and time of day of approach. Of 1137 potential organ donors, 661 (58%) consented and 476 (42%) declined. Consent rates were higher with matched race of donor and OPO representative (66% vs. 52%, p < 0.001), family approach by female OPO representative (67% vs. 56%, p = 0.002), if approach was initiated by OPO representative (69% vs. 49%, p < 0.001), and if consent rate was dependent on time of day the approach occurred: 6:00 am to noon (56%), noon to 6:00 pm (67%), 6:00 pm to midnight (68%), and midnight to 6:00 am (45%), p = 0.04. Family approach that led to consent lasted longer than those declining (67 vs. 43 minutes, p < 0.001). Independent predictors of consent to donation included female OPO representative (odds ratio [OR], 1.7; p = 0.006), approach discussion initiated by OPO representative (OR, 1.9; p = 0.001), and longer approach discussions (OR, 1.02; p < 0.001). The independent predictor of declined donation was the use of a translator (OR, 0.39; p = 0.01). Variables such as race and sex of OPO representative and time of day should be considered before approaching a family for organ donation. Avoiding translators during the approach process may improve donation rates. Education for health care providers should reinforce the importance of allowing OPO representatives to initiate the family approach for organ donation. Epidemiologic study, level IV. Therapeutic study, level IV.

Osmotic and hydraulic adjustment of mangrove saplings to extreme salinity.

PubMed

Méndez-Alonzo, Rodrigo; López-Portillo, Jorge; Moctezuma, Coral; Bartlett, Megan K; Sack, Lawren

2016-12-01

Salinity tolerance in plant species varies widely due to adaptation and acclimation processes at the cellular and whole-plant scales. In mangroves, extreme substrate salinity induces hydraulic failure and ion excess toxicity and reduces growth and survival, thus suggesting a potentially critical role for physiological acclimation to salinity. We tested the hypothesis that osmotic adjustment, a key type of plasticity that mitigates salinity shock, would take place in coordination with declines in whole-plant hydraulic conductance in a common garden experiment using saplings of three mangrove species with different salinity tolerances (Avicennia germinans L., Rhizophora mangle L. and Laguncularia racemosa (L.) C.F. Gaertn., ordered from higher to lower salinity tolerance). For each mangrove species, four salinity treatments (1, 10, 30 and 50 practical salinity units) were established and the time trajectories were determined for leaf osmotic potential (Ψ s ), stomatal conductance (g s ), whole-plant hydraulic conductance (K plant ) and predawn disequilibrium between xylem and substrate water potentials (Ψ pdd ). We expected that, for all three species, salinity increments would result in coordinated declines in Ψ s , g s and K plant , and that the Ψ pdd would increase with substrate salinity and time of exposure. In concordance with our predictions, reductions in substrate water potential promoted a coordinated decline in Ψ s , g s and K plant , whereas the Ψ pdd increased substantially during the first 4 days but dissipated after 7 days, indicating a time lag for equilibration after a change in substratum salinity. Our results show that mangroves confront and partially ameliorate acute salinity stress via simultaneous reductions in Ψ s , g s and K plant , thus developing synergistic physiological responses at the cell and whole-plant scales. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Finding parasites and finding challenges: improved diagnostic access and trends in reported malaria and anti-malarial drug use in Livingstone district, Zambia

PubMed Central

2012-01-01

Background Understanding the impact of malaria rapid diagnostic test (RDT) use on management of acute febrile disease at a community level, and on the consumption of anti-malarial medicines, is critical to the planning and success of scale-up to universal parasite-based diagnosis by health systems in malaria-endemic countries. Methods A retrospective study of district-wide community-level RDT introduction was conducted in Livingstone District, Zambia, to assess the impact of this programmed on malaria reporting, incidence of mortality and on district anti-malarial consumption. Results Reported malaria declined from 12,186 cases in the quarter prior to RDT introduction in 2007 to an average of 12.25 confirmed and 294 unconfirmed malaria cases per quarter over the year to September 2009. Reported malaria-like fever also declined, with only 4,381 RDTs being consumed per quarter over the same year. Reported malaria mortality declined to zero in the year to September 2009, and all-cause mortality declined. Consumption of artemisinin-based combination therapy (ACT) dropped dramatically, but remained above reported malaria, declining from 12,550 courses dispensed by the district office in the quarter prior to RDT implementation to an average of 822 per quarter over the last year. Quinine consumption in health centres also declined, with the district office ceasing to supply due to low usage, but requests for sulphadoxine-pyrimethamine (SP) rose to well above previous levels, suggesting substitution of ACT with this drug in RDT-negative cases. Conclusions RDT introduction led to a large decline in reported malaria cases and in ACT consumption in Livingstone district. Reported malaria mortality declined to zero, indicating safety of the new diagnostic regime, although adherence and/or use of RDTs was still incomplete. However, a deficiency is apparent in management of non-malarial fever, with inappropriate use of a low-cost single dose drug, SP, replacing ACT. While large gains have been achieved, the full potential of RDTs will only be realized when strategies can be put in place to better manage RDT-negative cases. PMID:23043557

Reliability of intraoperative neurophysiological monitoring using motor evoked potentials during resection of metastases in motor-eloquent brain regions: clinical article.

PubMed

Krieg, Sandro M; Schäffner, Michael; Shiban, Ehab; Droese, Doris; Obermüller, Thomas; Gempt, Jens; Meyer, Bernhard; Ringel, Florian

2013-06-01

Resection of gliomas in or adjacent to the motor system is widely performed using intraoperative neuromonitoring (IOM). For resection of cerebral metastases in motor-eloquent regions, however, data are sparse and IOM in such cases is not yet widely described. Since recent studies have shown that cerebral metastases infiltrate surrounding brain tissue, this study was undertaken to assess the value and influence of IOM during resection of supratentorial metastases in motor-eloquent regions. Between 2006 and 2011, the authors resected 206 consecutive supratentorial metastases, including 56 in eloquent motor areas with monitoring of monopolar direct cortically stimulated motor evoked potentials (MEPs). The authors evaluated the relationship between the monitoring data and the course of surgery, clinical data, and postoperative imaging. Motor evoked potential monitoring was successful in 53 cases (93%). Reduction of MEP amplitude correlated better with postoperative outcomes when the threshold for significant amplitude reduction was set at 80% (only > 80% reduction was considered significant decline) than when it was set at 50% (> 50% amplitude reduction was considered significant decline). Evidence of residual tumor was seen on MR images in 28% of the cases with significant MEP reduction. No residual tumor was seen in any case of stable MEP monitoring. Moreover, preoperative motor deficit, recursive partitioning analysis Class 3, and preoperative radiotherapy were independent risk factors for a new surgery-related motor weakness (occurring in 64% of patients with and 11% of patients without radiotherapy, p > 0.01). Continuous MEP monitoring provides reliable monitoring of the motor system and also influences the course of operation in resection of cerebral metastases. However, in establishing warning criteria, only an amplitude decline > 80% of the baseline should be considered significant.

BDNF is Associated With Age-Related Decline in Hippocampal Volume

PubMed Central

Erickson, Kirk I.; Prakash, Ruchika Shaurya; Voss, Michelle W.; Chaddock, Laura; Heo, Susie; McLaren, Molly; Pence, Brandt D.; Martin, Stephen A.; Vieira, Victoria J.; Woods, Jeffrey A.; Kramer, Arthur F.

2010-01-01

Hippocampal volume shrinks in late adulthood, but the neuromolecular factors that trigger hippocampal decay in aging humans remains a matter of speculation. In rodents, brain derived neurotrophic factor (BDNF) promotes the growth and proliferation of cells in the hippocampus and is important in long-term potentiation and memory formation. In humans, circulating levels of BDNF decline with advancing age and a genetic polymorphism for BDNF has been related to gray matter volume loss in old age. In this study, we tested whether age-related reductions in serum levels of BDNF would be related to shrinkage of the hippocampus and memory deficits in older adults. Hippocampal volume was acquired by automated segmentation of magnetic resonance images in 142 older adults without dementia. The caudate nucleus was also segmented and examined in relation to levels of serum BDNF. Spatial memory was tested using a paradigm in which memory load was parametrically increased. We found that increasing age was associated with smaller hippocampal volumes, reduced levels of serum BDNF, and poorer memory performance. Lower levels of BDNF were associated with smaller hippocampi and poorer memory, even when controlling for the variation related to age. In an exploratory mediation analysis, hippocampal volume mediated the age-related decline in spatial memory and BDNF mediated the age-related decline in hippocampal volume. Caudate nucleus volume was unrelated to BDNF levels or spatial memory performance. Our results identify serum BDNF as a significant factor related to hippocampal shrinkage and memory decline in late adulthood. PMID:20392958

An Age-Associated Decline in Thymic Output Differs in Dog Breeds According to Their Longevity.

PubMed

Holder, Angela; Mella, Stephanie; Palmer, Donald B; Aspinall, Richard; Catchpole, Brian

2016-01-01

The age associated decline in immune function is preceded in mammals by a reduction in thymic output. Furthermore, there is increasing evidence of a link between immune competence and lifespan. One approach to determining thymic output is to quantify signal joint T cell receptor excision circles (sj-TRECs), a method which has been developed and used in several mammalian species. Life expectancy and the rate of aging vary in dogs depending upon their breed. In this study, we quantified sj-TRECs in blood samples from dogs of selected breeds to determine whether there was a relationship between longevity and thymic output. In Labrador retrievers, a breed with a median expected lifespan of 11 years, there was an age-associated decline in sj-TREC values, with the greatest decline occurring before 5 years of age, but with sj-TREC still detectable in some geriatric animals, over 13 years of age. In large short-lived breeds (Burnese mountain dogs, Great Danes and Dogue de Bordeaux), the decline in sj-TREC values began earlier in life, compared with small long-lived breeds (Jack Russell terriers and Yorkshire terriers), and the presence of animals with undetectable sj-TRECs occurred at a younger age in the short-lived breeds. The study findings suggest that age-associated changes in canine sj-TRECs are related to breed differences in longevity, and this research highlights the use of dogs as a potential model of immunosenescence.

Distribution and decline of human pathogenic bacteria in soil after application in irrigation water and the potential for soil-splash-mediated dispersal onto fresh produce.

PubMed

Monaghan, J M; Hutchison, M L

2012-05-01

To improve our understanding of the survival and splash-mediated transfer of zoonotic agents and faecal indicator bacteria introduced into soils used for crop cultivation via contaminated irrigation waters. Zoonotic agents and an Escherichia coli marker bacterium were inoculated into borehole water, which was applied to two different soil types in early-, mid- and late summer. Decline of the zoonotic agents was influenced by soil type. Marker bacteria applied to columns of two soil types in irrigation water did not concentrate at the surface of the soils. Decline of zoonotic agents at the surface was influenced by soil type and environmental conditions. Typically, declines were rapid and bacteria were not detectable after 5 weeks. Selective agar strips were used to determine that the impact of water drops 24-87 μl could splash marker bacteria from soil surfaces horizontal distances of at least 25 cm and heights of 20 cm. Soil splash created by rain-sized water droplets can transfer enteric bacteria from soil to ready-to-eat crops. Persistence of zoonotic agents was reduced at the hottest part of the growing season when irrigation is most likely. Soil splash can cause crop contamination. We report the penetration depths and seasonally influenced declines of bacteria applied in irrigation water into two soil types. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Changes in the distribution of high-risk births associated with changes in contraceptive prevalence.

PubMed

Stover, John; Ross, John

2013-01-01

Several birth characteristics are associated with high mortality risk: very young or old mothers, short birth intervals and high birth order. One justification for family planning programs is the health benefits associated with better spacing and timing of births. This study examines the extent to which the prevalence of these risk factors changes as a country transitions from high to low fertility. We use data from 194 national surveys to examine both cross section and within-country variation in these risk factors as they relate to the total fertility rate. Declines in the total fertility rate are associated with large declines in the proportion of high order births, those to mothers over the age of 34 and those with multiple risk factors; as well as to increasing proportions of first order births. There is little change in the proportion of births with short birth intervals except in sub-Saharan Africa. The use of family planning is strongly associated with fertility declines. The proportion of second and higher order births with demographic risk factors declines substantially as fertility declines. This creates a potential for reducing child mortality rates. Some of the reduction comes from modifying the birth interval distribution or by bringing maternal age at the time of birth into the 'safe' range of 18-35 years, and some comes from the actual elimination of births that would have a high mortality risk (high parity births).

Age-related decline of precision and binding in visual working memory.

PubMed

Peich, Muy-Cheng; Husain, Masud; Bays, Paul M

2013-09-01

Working memory declines with normal aging, but the nature of this impairment is debated. Studies based on detecting changes to arrays of visual objects have identified two possible components to age-related decline: a reduction in the number of items that can be stored, or a deficit in maintaining the associations (bindings) between individual object features. However, some investigations have reported intact binding with aging, and specific deficits arising only in Alzheimer's disease. Here, using a recently developed continuous measure of recall fidelity, we tested the precision with which adults of different ages could reproduce from memory the orientation and color of a probed array item. The results reveal a further component of cognitive decline: an age-related decrease in the resolution with which visual information can be maintained in working memory. This increase in recall variability with age was strongest under conditions of greater memory load. Moreover, analysis of the distribution of errors revealed that older participants were more likely to incorrectly report one of the unprobed items in memory, consistent with an age-related increase in misbinding. These results indicate a systematic decline with age in working memory resources that can be recruited to store visual information. The paradigm presented here provides a sensitive index of both memory resolution and feature binding, with the potential for assessing their modulation by interventions. The findings have implications for understanding the mechanisms underpinning working memory deficits in both health and disease.

Age-Related Decline of Precision and Binding in Visual Working Memory

PubMed Central

2013-01-01

Working memory declines with normal aging, but the nature of this impairment is debated. Studies based on detecting changes to arrays of visual objects have identified two possible components to age-related decline: a reduction in the number of items that can be stored, or a deficit in maintaining the associations (bindings) between individual object features. However, some investigations have reported intact binding with aging, and specific deficits arising only in Alzheimer’s disease. Here, using a recently developed continuous measure of recall fidelity, we tested the precision with which adults of different ages could reproduce from memory the orientation and color of a probed array item. The results reveal a further component of cognitive decline: an age-related decrease in the resolution with which visual information can be maintained in working memory. This increase in recall variability with age was strongest under conditions of greater memory load. Moreover, analysis of the distribution of errors revealed that older participants were more likely to incorrectly report one of the unprobed items in memory, consistent with an age-related increase in misbinding. These results indicate a systematic decline with age in working memory resources that can be recruited to store visual information. The paradigm presented here provides a sensitive index of both memory resolution and feature binding, with the potential for assessing their modulation by interventions. The findings have implications for understanding the mechanisms underpinning working memory deficits in both health and disease. PMID:23978008

Declining hydraulic efficiency as transpiring leaves desiccate: two types of response.

PubMed

Brodribb, Tim J; Holbrook, N Michele

2006-12-01

The conductance of transpiring leaves to liquid water (Kleaf) was measured across a range of steady-state leaf water potentials (Psileaf). Manipulating the transpiration rate in excised leaves enabled us to vary Psileaf in the range -0.1 MPa to less than -1.5 MPa while using a flowmeter to monitor the transpiration stream. Employing this technique to measure how desiccation affects Kleaf in 19 species, including lycophytes, ferns, gymnosperms and angiosperms, we found two characteristic responses. Three of the six angiosperm species sampled maintained a steady maximum Kleaf while Psileaf remained above -1.2 MPa, although desiccation of leaves beyond this point resulted in a rapid decline in Kleaf. In all other species measured, declining Psileaf led to a proportional decrease in Kleaf, such that midday Psileaf of unstressed plants in the field was sufficient to depress Kleaf by an average of 37%. It was found that maximum Kleaf was strongly correlated with maximum CO2 assimilation rate, while Kleaf = 0 occurred at a Psileaf slightly less negative than at leaf turgor loss. A strong linear correlation across species between Psileaf at turgor loss and Psileaf at Kleaf = 0 raises the possibility that declining Kleaf was related to declining cell turgor in the leaf prior to the onset of vein cavitation. The vulnerability of leaves rehydrating after desiccation was compared with vulnerability of leaves during steady-state evaporation, and differences between methods suggest that in many cases vein cavitation occurs only as Kleaf approaches zero.

Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis

PubMed Central

2014-01-01

Background Bilateral regional brain oxygen saturation (rSO2) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO2 values as a warning sign for the development of different types of decline in postoperative psychological function. Methods Observational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO2 intraoperative values were recorded. An absolute rSO2 value of <50% or a reduction of >20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms. Results We observed no differences in baseline rSO2 values; rSO2 decreased significantly in all patients during surgery (P < 0.0001). Seventy-five patients (60%) had no sign of cognitive decline or psychological symptoms. Twenty-one patients (16.8%) had memory decline, 3 (2.4%) had VM-EF decline, and 33 (26.4%) had psychological symptoms. Left and right rSO2 values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO2 was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034). Conclusions Detection of a trend to asymmetry in rSO2 values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years. PMID:25061427

Ginkgo Biloba Extract and Long-Term Cognitive Decline: A 20-Year Follow-Up Population-Based Study

PubMed Central

Amieva, Hélène; Meillon, Céline; Helmer, Catherine; Barberger-Gateau, Pascale; Dartigues, Jean François

2013-01-01

Background Numerous studies have looked at the potential benefits of various nootropic drugs such as Ginkgo biloba extract (EGb761®; Tanakan®) and piracetam (Nootropyl®) on age-related cognitive decline often leading to inconclusive results due to small sample sizes or insufficient follow-up duration. The present study assesses the association between intake of EGb761® and cognitive function of elderly adults over a 20-year period. Methods and Findings The data were gathered from the prospective community-based cohort study ‘Paquid’. Within the study sample of 3612 non-demented participants aged 65 and over at baseline, three groups were compared: 589 subjects reporting use of EGb761® at at least one of the ten assessment visits, 149 subjects reporting use of piracetam at one of the assessment visits and 2874 subjects not reporting use of either EGb761® or piracetam. Decline on MMSE, verbal fluency and visual memory over the 20-year follow-up was analysed with a multivariate mixed linear effects model. A significant difference in MMSE decline over the 20-year follow-up was observed in the EGb761® and piracetam treatment groups compared to the ‘neither treatment’ group. These effects were in opposite directions: the EGb761® group declined less rapidly than the ‘neither treatment’ group, whereas the piracetam group declined more rapidly (β = −0.6). Regarding verbal fluency and visual memory, no difference was observed between the EGb761® group and the ‘neither treatment’ group (respectively, β = 0.21 and β = −0.03), whereas the piracetam group declined more rapidly (respectively, β = −1.40 and β = −0.44). When comparing the EGb761® and piracetam groups directly, a different decline was observed for the three tests (respectively β = −1.07, β = −1.61 and β = −0.41). Conclusion Cognitive decline in a non-demented elderly population was lower in subjects who reported using EGb761® than in those who did not. This effect may be a specific medication effect of EGb761®, since it was not observed for another nootropic medication, piracetam. PMID:23326356

Relationship between intraoperative regional cerebral oxygen saturation trends and cognitive decline after total knee replacement: a post-hoc analysis.

PubMed

Salazar, Fátima; Doñate, Marta; Boget, Teresa; Bogdanovich, Ana; Basora, Misericordia; Torres, Ferran; Gracia, Isabel; Fàbregas, Neus

2014-01-01

Bilateral regional brain oxygen saturation (rSO2) trends, reflecting intraoperative brain oxygen imbalance, could warn of brain dysfunction. Various types of cognitive impairment, such as memory decline, alterations in executive function or subjective complaints, have been described three months after surgery. Our aim was to explore the potential utility of rSO2 values as a warning sign for the development of different types of decline in postoperative psychological function. Observational post-hoc analysis of data for the patient sample (n = 125) of a previously conducted clinical trial in patients over the age of 65 years undergoing total knee replacement under spinal anesthesia. Demographic, hemodynamic and bilateral rSO2 intraoperative values were recorded. An absolute rSO2 value of <50% or a reduction of >20% or >25% below baseline were chosen as relevant cutoffs. Composite function test scores were created from baseline to three months for each patient and adjusted for the mean (SD) score changes for a control group (n = 55). Tests were used to assess visual-motor coordination and executive function (VM-EF) (Wechsler Digit Symbol-Coding and Visual Reproduction, Trail Making Test) and memory (Auditory Verbal Learning, Wechsler Memory Scale); scales were used to assess psychological symptoms. We observed no differences in baseline rSO2 values; rSO2 decreased significantly in all patients during surgery (P < 0.0001). Seventy-five patients (60%) had no sign of cognitive decline or psychological symptoms. Twenty-one patients (16.8%) had memory decline, 3 (2.4%) had VM-EF decline, and 33 (26.4%) had psychological symptoms. Left and right rSO2 values were asymmetric in patients who had memory decline (mean [SD] left-right ratio of 95.03 [8.51] vs 101.29 [6.7] for patients with no changes, P = 0.0012). The mean right-left difference in rSO2 was also significant in these patients (-2.87% [4.73%], lower on the right, P = 0.0034). Detection of a trend to asymmetry in rSO2 values can warn of possible postoperative onset of memory decline. Psychological symptoms and memory decline were common three months after knee replacement in our patients over the age of 65 years.

Examining the impact of grape consumption on brain metabolism and cognitive function in patients with mild decline in cognition: A double-blinded placebo controlled pilot study.

PubMed

Lee, Jooyeon; Torosyan, Nare; Silverman, Daniel H

2017-01-01

Natural compounds in grapes such as resveratrol are known for their antioxidant and anti-inflammatory properties. Some studies have shown a potential role for grapes or wine in slowing cognitive decline and other effects of aging. However, well-controlled experimental data obtained in human subjects are still in need of further development. Here we aimed to systematically assess effects of grapes on regional cerebral metabolism. Ten subjects with mild decline in cognition (mean, 72.2±4.7years; 50% female) were included in this analysis. Participants were randomized into an active grape formulation arm or a placebo arm which consumed a formulation free of polyphenols for six months. Cognitive performance was measured through neuropsychological assessments performed at baseline and 6months after initiation of therapy. Changes in brain metabolism occurring with each therapy regimen were assessed by brain PET scans with the radiotracer [F-18] fluorodeoxyglucose (FDG), obtained during initial evaluation and 6months later. Standardized volumes of interest (sVOI) and statistical parametric mapping (SPM) methods were applied to FDG-PET scans to identify significant regional cerebral metabolic changes. In contrast to participants taking the active grape formulation, who displayed no significant decline in metabolism, the placebo arm underwent significant metabolic decline in sVOI's of the right posterior cingulate cortex (p=0.01), and left superior posterolateral temporal cortex (p=0.04). SPM analyses also found significant declines in the placebo group, particularly in left prefrontal, cingulate, and left superior posterolateral temporal cortex (p<0.01) with stable brain metabolism in the active formulation arm. No significant differences were seen in scores on the neuropsychological battery of tests between the two groups. However, metabolism in right superior parietal cortex and left inferior anterior temporal cortex was correlated with improvements in attention/working memory, as measured with WAIS-III Digital Span within the active formulation group (r=-0.69, p=0.04). The placebo arm had declines in regions of the brain known to be significantly affected in the early stages of Alzheimer's disease, while the active formulation group was spared such decline. This suggests a protective effect of grapes against early pathologic metabolic decline. Copyright © 2016 Elsevier Inc. All rights reserved.

Human Neural Stem Cell Transplantation Ameliorates Radiation-Induced Cognitive Dysfunction

PubMed Central

Acharya, Munjal M.; Christie, Lori-Ann; Lan, Mary L.; Giedzinski, Erich; Fike, John R.; Rosi, Susanna; Limoli, Charles L.

2012-01-01

Cranial radiotherapy induces progressive and debilitating declines in cognition that may, in part, be caused by the depletion of neural stem cells. The potential of using stem cell replacement as a strategy to combat radiation-induced cognitive decline was addressed by irradiating athymic nude rats followed 2 days later by intrahippocampal transplantation with human neural stem cells (hNSC). Measures of cognitive performance, hNSC survival, and phenotypic fate were assessed at 1 and 4 months after irradiation. Irradiated animals engrafted with hNSCs showed significantly less decline in cognitive function than irradiated, sham-engrafted animals and acted indistinguishably from unirradiated controls. Unbiased stereology revealed that 23% and 12% of the engrafted cells survived 1 and 4 months after transplantation, respectively. Engrafted cells migrated extensively, differentiated along glial and neuronal lineages, and expressed the activity-regulated cytoskeleton-associated protein (Arc), suggesting their capability to functionally integrate into the hippocampus. These data show that hNSCs afford a promising strategy for functionally restoring cognition in irradiated animals. PMID:21757460

Outsourcing Memory in Response to an Aging Population.

PubMed

Ross, Michael; Schryer, Emily

2015-11-01

With baby boomers entering old age and longevity increasing, policymakers have focused on the physical, social, and health needs of older persons. We urge policymakers to consider cognitive aging as well, particularly normal, age-related memory decline. Psychological scientists attribute memory decline mainly to cognitive overload stemming from age-related reductions in sensory capacities, speed of cognitive processing, and the ability to filter out irrelevant information. Even in the absence of decline, however, memory is imperfect and forgetting can be especially consequential for older adults. For example, forgetting to take prescription medicines is an age-related problem largely because older adults tend to ingest many more prescription drugs. We propose that policymakers focus on increasing environmental support for memory that can reduce the burden on cognitive resources and thus improve recall. In providing environmental support, policymakers need to pay careful attention to potential age-related changes in physical and cognitive capacity, as well as behavior. © The Author(s) 2015.

Protective Role of Recent and Past Long-Term Physical Activity on Age-Related Cognitive Decline: The Moderating Effect of Sex.

PubMed

Lopez-Fontana, Iréné; Castanier, Carole; Le Scanff, Christine; Perrot, Alexandra

2018-06-13

This study aimed to investigate if the impact of both recent and long-term physical activity on age-related cognitive decline would be modified by sex. One-hundred thirty-five men (N = 67) and women (N = 68) aged 18 to 80 years completed the Modifiable Activity Questionnaire and the Historical Leisure Activity Questionnaire. A composite score of cognitive functions was computed from five experimental tasks. Hierarchical regression analyses performed to test the moderating effect of recent physical activity on age-cognition relationship had not revealed significant result regardless of sex. Conversely, past long-term physical activity was found to slow down the age-related cognitive decline among women (β = 0.22, p = .03), but not men. The findings support a lifecourse approach in identifying determinants of cognitive aging and the importance of taking into account the moderating role of sex. This article presented potential explanations for these moderators and future avenues to explore.

Long-term changes in fish mercury levels in the historically impacted English-Wabigoon River system (Canada).

PubMed

Neff, Margaret R; Bhavsar, Satyendra P; Arhonditsis, George B; Fletcher, Rachael; Jackson, Donald A

2012-09-01

The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lake Whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. For all lakes and species, there is a significant decline (36-94%) in mercury concentrations through time; however, there is evidence that this decline is either slowing down or levelling off. Concentrations in the English-Wabigoon fish are elevated, and may still present a potential health risk to humans consuming fish from this system. Various biotic and abiotic factors are examined as possible explanations to slowing rates of decline in mercury concentrations observed in the mid-1980s.

Mechanisms of change in ERP treatment of compulsive hand washing: does primary threat make a difference?

PubMed

Cougle, Jesse R; Wolitzky-Taylor, Kate B; Lee, Han-Joo; Telch, Michael J

2007-07-01

The present study sought to examine patterns of habituation in exposure and response prevention (ERP) treatment of compulsive hand washing. Sub-clinical compulsive washers (n=27) with illness or non-illness primary threats were compared in order to detect potential differences in response to a single session of ERP. Changes in anxiety, disgust, and urge to wash were analyzed, and significant reductions in both anxiety and disgust were noted. Urge to wash significantly declined among washers primarily concerned with illness; among those concerned with non-illness threats, urge to wash did not significantly decline. Moreover, anxiety was found to decline when controlling for disgust and vice versa. Lastly, when both anxiety and disgust were entered into a model predicting changes in urge to wash, anxiety but not disgust predicted urge to wash for those with illness-related threats; for washers with non-illness threats, the findings were the reverse. Several clinical and theoretical implications are discussed.

CO2 leakage-induced vegetation decline is primarily driven by decreased soil O2.

PubMed

Zhang, Xueyan; Ma, Xin; Zhao, Zhi; Wu, Yang; Li, Yue

2016-04-15

To assess the potential risks of carbon capture and storage (CCS), studies have focused on vegetation decline caused by leaking CO2. Excess soil CO2 caused by leakage can affect soil O2 concentrations and soil pH, but how these two factors affect plant development remains poorly understood. This hinders the selection of appropriate species to mitigate potential negative consequences of CCS. Through pot experiments, we simulated CO2 leakage to examine its effects on soil pH and soil O2 concentrations. We subsequently assessed how maize growth responded to these changes in soil pH and O2. Decreased soil O2 concentrations significantly reduced maize biomass, and explained 69% of the biomass variation under CO2 leakage conditions. In contrast, although leaked CO2 changed soil pH significantly (from 7.32 to 6.75), it remained within the optimum soil pH range for maize growth. This suggests that soil O2 concentration, not soil pH, influences plant growth in these conditions. Therefore, in case of potential CO2 leakage risks, hypoxia-tolerant species should be chosen to improve plant survival, growth, and yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

Seagrass epiphytes: useful indicator, potential biological criterion, or forlorn hope?

EPA Science Inventory

Epiphytes on seagrasses have been studied for more than 50 years, and proposed as an indicator of anthropogenic nutrient enrichment for over 30 years. Epiphytes have been correlated with seagrass declines, causally related to nutrient additions in both field and mesocosm experim...

Dietary Change Interventions for Undergraduate Populations: Systematic Review and Recommendations

ERIC Educational Resources Information Center

Pember, Sarah E.; Knowlden, Adam P.

2017-01-01

Background: Research demonstrates a decline in healthy eating behaviors during transitional years at university, potentially leading to weight gain and establishing maladaptive dietary habits. Purpose: This systematic review assessed the efficacy of previous nutrition interventions for undergraduates, evaluating design and implementation. Methods:…

STREAM FISH HABITAT SUITABILITY AND THE RISK OF POPULATION DECLINE

EPA Science Inventory

Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

Estimated Ultraviolet Radiation Doses in Wetlands in Six National Parks

EPA Science Inventory

Ultraviolet radiation (UVR) has been suggested as a potential cause of population declines and increases in malformations in amphibians. This study indicates that the present distributions of amphibians in four western U.S. National Parks are not related to UVR exposure, and sugg...

Enhancing resource availability in agro-ecosystems for beneficial arthropods through floral provisioning

USDA-ARS?s Scientific Manuscript database

There has been a decline in beneficial arthropods (insects and spiders) including pollinators because of habitat destruction and intense management practices. Enhancing landscapes with additional floral and other non-crop habitats has the potential to attract pollinators, and predatory arthropods wh...

The effects of ingested aqueous aluminum on floral fidelity and foraging strategy in honey bees (Apis mellifera).

PubMed

Chicas-Mosier, Ana M; Cooper, Bree A; Melendez, Alexander M; Pérez, Melina; Oskay, Devrim; Abramson, Charles I

2017-09-01

Pollinator decline is of international concern because of the economic services these organisms provide. Commonly cited sources of decline are toxicants, habitat fragmentation, and parasites. Toxicant exposure can occur through uptake and distribution from plant tissues and resources such as pollen and nectar. Metals such as aluminum can be distributed to pollinators and other herbivores through this route especially in acidified or mined areas. A free-flying artificial flower patch apparatus was used to understand how two concentrations of aluminum (2mg/L and 20mg/L) may affect the learning, orientation, and foraging behaviors of honey bees (Apis mellifera) in Turkey. The results show that a single dose of aluminum immediately affects the floral decision making of honey bees potentially by altering sucrose perception, increasing activity level, or reducing the likelihood of foraging on safer or uncontaminated resource patches. We conclude that aluminum exposure may be detrimental to foraging behaviors and potentially to other ecologically relevant behaviors. Copyright © 2017. Published by Elsevier Inc.

Iron-sulfur protein in mitochondrial complexes of Spodoptera litura as potential site for ROS generation.

PubMed

Li, Liangde; Dong, Xiaolin; Shu, Benshui; Wang, Zheng; Hu, Qiongbo; Zhong, Guohua

2014-12-01

Mitochondrial complex I is the main source of reactive oxygen species (ROS) production, but the exact site of superoxide generation or their relative contribution is not clear. This study aims to determine the function of iron-sulfur clusters (ISCU) in the initiation of ROS generation. ISCU2 and ISCU8 were cloned from Spodoptera litura which shared the conserved amino acid sequence with other insects. The expressions of the two genes were ubiquitous throughout the whole development stages and tissues. Knockdown of ISCU2 and ISCU8 resulted in the decline of the ROS, whereas rotenone and azadirachtin treatment up-regulated ROS levels by increasing mRNA expression. Furthermore, antioxidant enzyme activity of SOD and POD were up-regulated by rotenone and azadirachtin treatment and then declined after ISCU was silenced. Our results suggest the possibility that the molecules of ISCU2 and ISCU8 in complex I may serve as potential sites in the initiation of ROS generation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Promoting Declines in the Prevalence of Late-Life Disability: Comparisons of Three Potentially High-Impact Interventions

PubMed Central

Freedman, Vicki A; Hodgson, Nancy; Lynn, Joanne; Spillman, Brenda C; Waidmann, Timothy; Wilkinson, Anne M; Wolf, Douglas A

2006-01-01

Although the prevalence of late-life disability has been declining, how best to promote further reductions remains unclear. This article develops and then demonstrates an approach for comparing the effects of interventions on the prevalence of late-life disability. We review evidence for three potentially high-impact strategies: physical activity, depression screening and treatment, and fall prevention. Because of the large population at risk for falling, the demonstrated efficacy of multi-component interventions in preventing falls, and the strong links between falls and disability, we conclude that, in the short run, multi-component fall-prevention efforts would likely have a higher impact than either physical activity or depression screening and treatment. However, longer-term comparisons cannot be made based on the current literature and may differ from short-run conclusions, since increases in longevity may temper the influences of these interventions on prevalence. Additional research is needed to evaluate longer-term outcomes of interventions, including effects on length and quality of life. PMID:16953808

Landowner and practitioner perspectives on private land conservation programs

USGS Publications Warehouse

Lute, Michelle L.; Gillespie, Caitlyn R.; Fontaine, Joseph J.; Martin, Dustin R.

2018-01-01

Efforts to reverse declines in native grasslands benefit from agricultural policies that encourage private land conservation. The U.S. Department of Agriculture’s Conservation Reserve Program (CRP) improved conservation across landscapes but enrollment has declined. We used sequential exploratory mixed methods to compare landowner and conservation practitioners’ perceptions, evaluate perceived benefits, and identify potential improvements to CRP. Focus groups of practitioners informed a quantitative survey of landowners who had properties >160 total acres in Nebraska. Results suggest potential misalignment in perceptions between practitioners and landowners. Practitioners were concerned that conservation, especially of wildlife, was secondary to profit. But the majority of landowners valued CRP-related ecosystem services, including native pollinators. Practitioners posited that younger landowners were primarily profit motivated, but CRP enrollment did not differ by demographics. Practitioners and landowners identified rule complexity as a major challenge and practitioner–landowner relationships as critical to success. Findings suggest that practitioners may underestimate non-economic motivations and illuminate opportunities to encourage private land conservation.

Temporal analysis of mtDNA variation reveals decreased genetic diversity in least terns

USGS Publications Warehouse

Draheim, Hope M.; Baird, Patricia; Haig, Susan M.

2012-01-01

The Least Tern (Sternula antillarum) has undergone large population declines over the last century as a result of direct and indirect anthropogenic factors. The genetic implications of these declines are unknown. We used historical museum specimens (pre-1960) and contemporary (2001–2005) samples to examine range-wide phylogeographic patterns and investigate potential loss in the species' genetic variation. We obtained sequences (522 bp) of the mitochondrial gene for NADH dehydrogenase subunit 6 (ND6) from 268 individuals from across the species' range. Phylogeographic analysis revealed no association with geography or traditional subspecies designations. However, we detected potential reductions in genetic diversity in contemporary samples from California and the Atlantic coast Least Tern from that in historical samples, suggesting that current genetic diversity in Least Tern populations is lower than in their pre-1960 counterparts. Our results offer unique insights into changes in the Least Tern's genetic diversity over the past century and highlight the importance and utility of museum specimens in studies of conservation genetics.

Aging and sarcopenia associate with specific interactions between gut microbes, serum biomarkers and host physiology in rats

PubMed Central

Karaz, Sonia; Morin-Rivron, Delphine; Masoodi, Mojgan; Feige, Jerome N.; Parkinson, Scott James

2017-01-01

The microbiome has been demonstrated to play an integral role in the maintenance of many aspects of health that are also associated with aging. In order to identify areas of potential exploration and intervention, we simultaneously characterized age-related alterations in gut microbiome, muscle physiology and serum proteomic and lipidomic profiles in aged rats to define an integrated signature of the aging phenotype. We demonstrate that aging skews the composition of the gut microbiome, in particular by altering the Sutterella to Barneseilla ratio, and alters the metabolic potential of intestinal bacteria. Age-related changes of the gut microbiome were associated with the physiological decline of musculoskeletal function, and with molecular markers of nutrient processing/availability, and inflammatory/immune status in aged versus adult rats. Altogether, our study highlights that aging leads to a complex interplay between the microbiome and host physiology, and provides candidate microbial species to target physical and metabolic decline during aging by modulating gut microbial ecology. PMID:28783713

Aging and sarcopenia associate with specific interactions between gut microbes, serum biomarkers and host physiology in rats.

PubMed

Siddharth, Jay; Chakrabarti, Anirikh; Pannérec, Alice; Karaz, Sonia; Morin-Rivron, Delphine; Masoodi, Mojgan; Feige, Jerome N; Parkinson, Scott James

2017-07-17

The microbiome has been demonstrated to play an integral role in the maintenance of many aspects of health that are also associated with aging. In order to identify areas of potential exploration and intervention, we simultaneously characterized age-related alterations in gut microbiome, muscle physiology and serum proteomic and lipidomic profiles in aged rats to define an integrated signature of the aging phenotype. We demonstrate that aging skews the composition of the gut microbiome, in particular by altering the Sutterella to Barneseilla ratio, and alters the metabolic potential of intestinal bacteria. Age-related changes of the gut microbiome were associated with the physiological decline of musculoskeletal function, and with molecular markers of nutrient processing/availability, and inflammatory/immune status in aged versus adult rats. Altogether, our study highlights that aging leads to a complex interplay between the microbiome and host physiology, and provides candidate microbial species to target physical and metabolic decline during aging by modulating gut microbial ecology.

IGF-1, the Cross Road of the Nutritional, Inflammatory and Hormonal Pathways to Frailty

PubMed Central

Maggio, Marcello; De Vita, Francesca; Lauretani, Fulvio; Buttò, Valeria; Bondi, Giuliana; Cattabiani, Chiara; Nouvenne, Antonio; Meschi, Tiziana; Dall’Aglio, Elisabetta; Ceda, Gian Paolo

2013-01-01

The decline in functional capacity is a heterogeneous phenomenon in the elderly. An accelerated ageing determines a frail status. It results in an increased vulnerability to stressors for decreased physiological reserves. The early identification of a frail status is essential for preventing loss of functional capacity, and its clinical consequences. Frailty and mobility limitation result from an interplay of different pathways including multiple anabolic deficiency, inflammation, oxidative stress, and a poor nutritional status. However, the age-related decline in insulin-like growth factor 1 (IGF-1) bioactivity deserves special attention as it could represent the ideal crossroad of endocrine, inflammatory, and nutritional pathways to frailty. Several minerals, namely magnesium, selenium, and zinc, appear to be important determinants of IGF-1 bioactivity. This review aims to provide an overview of the potential usefulness of nutrients modulating IGF-1 as potential therapeutic targets in the prevention of mobility limitation occurring in frail older subjects. PMID:24152751

Pulmonary function outcomes for assessing cystic fibrosis care.

PubMed

Wagener, Jeffrey S; Elkin, Eric P; Pasta, David J; Schechter, Michael S; Konstan, Michael W; Morgan, Wayne J

2015-05-01

Assessing cystic fibrosis (CF) patient quality of care requires the choice of an appropriate outcome measure. We looked systematically and in detail at pulmonary function outcomes that potentially reflect clinical practice patterns. Epidemiologic Study of Cystic Fibrosis data were used to evaluate six potential outcome variables (2002 best FVC, FEV(1), and FEF(25-75) and rate of decline for each from 2000 to 2002). We ranked CF care sites by outcome measure and then assessed any association with practice patterns and follow-up pulmonary function. Sites ranked in the top quartile had more frequent monitoring, treatment of exacerbations, and use of chronic therapies and oral corticosteroids. The follow-up rate of pulmonary function decline was not predicted by site ranking. Different pulmonary function outcomes associate slightly differently with practice patterns, although annual FEV(1) is at least as good as any other measure. Current site ranking only moderately predicts future ranking. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Smad4 restricts differentiation to promote expansion of satellite cell derived progenitors during skeletal muscle regeneration.

PubMed

Paris, Nicole D; Soroka, Andrew; Klose, Alanna; Liu, Wenxuan; Chakkalakal, Joe V

2016-11-18

Skeletal muscle regenerative potential declines with age, in part due to deficiencies in resident stem cells (satellite cells, SCs) and derived myogenic progenitors (MPs); however, the factors responsible for this decline remain obscure. TGFβ superfamily signaling is an inhibitor of myogenic differentiation, with elevated activity in aged skeletal muscle. Surprisingly, we find reduced expression of Smad4 , the downstream cofactor for canonical TGFβ superfamily signaling, and the target Id1 in aged SCs and MPs during regeneration. Specific deletion of Smad4 in adult mouse SCs led to increased propensity for terminal myogenic commitment connected to impaired proliferative potential. Furthermore, SC-specific Smad4 disruption compromised adult skeletal muscle regeneration. Finally, loss of Smad4 in aged SCs did not promote aged skeletal muscle regeneration. Therefore, SC-specific reduction of Smad4 is a feature of aged regenerating skeletal muscle and Smad4 is a critical regulator of SC and MP amplification during skeletal muscle regeneration.

Nitrous oxide fluxes from a claypan soil overlying nitrate-enriched glacial drift

USGS Publications Warehouse

Pomes, M.L.; Wilkison, D.H.; McMahon, P.B.

1998-01-01

The closed chamber method was used to assess nitrous oxide (N2O) fluxes from corn (Zea mays, L.) fields during the 1995 growing season. The study area was characterized by a claypan soil overlying a nitrate (NO31-)-enriched glacial-drift aquifer. Denitrification produced N2O fluxes of 0.2-6.9 g ha-1 hr-1 early in the growing season. Fluxes increased with increasing soil temperature, soil water potential, and soil saturation. However, greatly diminished N2O fluxes (0.001-0.09 gha-1 hr-1) occurred when soil saturation increased to 94 percent. Losses of N2O increased linearly during the day and decreased at night, probably because of declining soil temperatures. Declines in soil saturation (less than 80 percent) and soil moisture potential (less than -10 kPa) produced late season N2O fluxes (0.03-0.8 g ha-1 hr-1) attributable to nitrification. Results indicate that denitrification would not significantly reduce claypan soil NO31- concentrations.

Contrasting patterns of changes in abundance following a bleaching event between juvenile and adult scleractinian corals

NASA Astrophysics Data System (ADS)

Álvarez-Noriega, Mariana; Baird, Andrew H.; Bridge, Tom C. L.; Dornelas, Maria; Fontoura, Luisa; Pizarro, Oscar; Precoda, Kristin; Torres-Pulliza, Damaris; Woods, Rachael M.; Zawada, Kyle; Madin, Joshua S.

2018-06-01

Coral bleaching events have caused extensive mortality on reefs around the world. Juvenile corals are generally less affected by bleaching than their conspecific adults and therefore have the potential to buffer population declines and seed recovery. Here, we use juvenile and adult abundance data at 20 sites encircling Lizard Island, Great Barrier Reef, before and after the 2016 bleaching event to quantify: (1) correlates of changes in juvenile abundance following a bleaching event; (2) differences in susceptibility to extreme thermal stress between juveniles and adults. Declines in juvenile abundance were lower at sites closer to the 20-m-depth contour and higher for Acropora and Pocillopora juveniles than for other taxa. Juveniles of Acropora and Goniastrea were less susceptible to bleaching than adults, but the opposite was true for Pocillopora spp. and taxa in the family Merulinidae. Our results indicate that the potential of the juvenile life stage to act as a buffer during bleaching events is taxon-dependent.

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS

PubMed Central

Foltynie, Tom; Zrinzo, Ludvic; Hyam, Jonathan A.; Limousin, Patricia

2017-01-01

Objective. Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS) for Parkinson's disease (PD). The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed. Method. In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS. Results. As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed. Discussion. Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS. PMID:28408788

Steep declines in atmospheric base cations in regions of Europe and North America

NASA Astrophysics Data System (ADS)

Hedin, Lars O.; Granat, Lennart; Likens, Gene E.; Adri Buishand, T.; Galloway, James N.; Butler, Thomas J.; Rodhe, Henning

1994-01-01

HUMAN activities have caused marked changes in atmospheric chemistry over large regions of Europe and North America. Although considerable attention has been paid to the effects of changes in the deposition of acid anions (such as sulphate and nitrate) on terrestrial and aquatic ecosystems1-7, little is known about whether the concentrations of basic components of the atmosphere have changed over time8,9 and what the biogeochemical consequences of such potential changes might be. In particular, there has been some controversy8-12 as to whether declines in base-cation deposition have countered effects of recent reductions in SO2emission. Here we report evidence for steep declines in the atmospheric concentrations of base cations (sum of non-sea-salt Ca2+, Mg2+, K+ and Na+) over the past 10 to 26 years from high-quality precipitation chemistry records in Europe and North America. To varying but generally significant degrees, these base-cation trends have offset recent reductions in sulphate deposition in the regions examined. The observed trends seem to be ecologically important on decadal timescales, and support earlier contentions8-10 that declines in the deposition of base cations may have contributed to increased sensitivity of poorly buffered ecosystems.

Optical characteristics of natural waters protect amphibians from UV-B in the U.S. Pacific Northwest

USGS Publications Warehouse

Palen, Wendy J.; Schindler, David E.; Adams, Michael J.; Pearl, Christopher A.; Bury, R. Bruce; Diamond, S.A.

2002-01-01

Increased exposure to ultraviolet-B (UV-B) radiation has been proposed as a major environmental stressor leading to global amphibian declines. Prior experimental evidence from the U.S. Pacific Northwest (PNW) indicating the acute embryonic sensitivity of at least four amphibian species to UV-B has been central to the literature about amphibian decline. However, these results have not been expanded to address population-scale effects and natural landscape variation in UV-B transparency of water at amphibian breeding sites: both necessary links to assess the importance of UV-B for amphibian declines. We quantified the UV-B transparency of 136 potential amphibian breeding sites to establish the pattern of UV-B exposure across two montane regions in the PNW. Our data suggest that 85% of sites are naturally protected by dissolved organic matter in pond water, and that only a fraction of breeding sites are expected to experience UV-B intensities exceeding levels associated with elevated egg mortality. Thus, the spectral characteristics of natural waters likely mediate the physiological effects of UV-B on amphibian eggs in all but the clearest waters. These data imply that UV-B is unlikely to cause broad amphibian declines across the landscape of the American Northwest.

Epigenetic regulation of neuronal immediate early genes is associated with decline in their expression and memory consolidation in scopolamine-induced amnesic mice.

PubMed

Srivas, Sweta; Thakur, Mahendra K

2017-09-01

Recently, we reported a correlation of scopolamine mediated decline in memory consolidation with increase in the expression of DNA methyltransferase 1 (DNMT1) and histone deacetylase 2 (HDAC2) in the mouse hippocampus. Memory consolidation is a protein synthesis-dependent process which involves the expression of synaptic plasticity genes, particularly neuronal immediate early genes (IEGs). However, the mechanism of regulation of these genes during decline in memory is poorly understood. Therefore, we have studied the epigenetic regulation of expression of neuronal IEGs in scopolamine-induced amnesic mice. Scopolamine significantly impaired memory consolidation as tested by radial arm maze, and the expression of neuronal IEGs was downregulated in the hippocampus as revealed by qRT-PCR and Western blotting. Further, methylated DNA immunoprecipitation (MeDIP) analysis showed increase in DNA methylation, while chromatin immunoprecipitation (ChIP) revealed decrease in H3K9/14 acetylation at the promoter of neuronal IEGs. Taken together, the present study shows that increased DNA methylation and decreased histone acetylation at the promoter of neuronal IEGs are associated with decline in their expression and memory consolidation during scopolamine-induced amnesia. These findings suggest that the epigenetic regulation through altered DNA methylation and histone acetylation might be explored further to develop potential therapeutic interventions for amnesia.

Rapid warming accelerates tree growth decline in semi-arid forests of Inner Asia.

PubMed

Liu, Hongyan; Park Williams, A; Allen, Craig D; Guo, Dali; Wu, Xiuchen; Anenkhonov, Oleg A; Liang, Eryuan; Sandanov, Denis V; Yin, Yi; Qi, Zhaohuan; Badmaeva, Natalya K

2013-08-01

Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi-arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi-arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi-arid forests, where growing season water stress has been rising due to warming-induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi-arid sites is corroborated by correlation analyses comparing annual climate data to records of tree-ring widths. These ring-width records tend to be substantially more sensitive to drought variability at semi-arid sites than at semi-humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007-2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi-arid forests. © 2013 John Wiley & Sons Ltd.

The Longitudinal Impact of Cognitive Speed of Processing Training on Driving Mobility

PubMed Central

Edwards, Jerri D.; Myers, Charlsie; Ross, Lesley A.; Roenker, Daniel L.; Cissell, Gayla M.; McLaughlin, Alexis M.; Ball, Karlene K.

2009-01-01

Purpose: To examine how cognitive speed of processing training affects driving mobility across a 3-year period among older drivers. Design and Methods: Older drivers with poor Useful Field of View (UFOV) test performance (indicating greater risk for subsequent at-fault crashes and mobility declines) were randomly assigned to either a speed of processing training or a social and computer contact control group. Driving mobility of these 2 groups was compared with a group of older adults who did not score poorly on the UFOV test (reference group) across a 3-year period. Results: Older drivers with poor UFOV test scores who did not receive training experienced greater mobility declines as evidenced by decreased driving exposure and space and increased driving difficulty at 3 years. Those at risk for mobility decline who received training did not differ across the 3-year period from older adults in the reference group with regard to driving exposure, space, and most aspects of driving difficulty. Implications: Cognitive speed of processing training can not only improve cognitive performance but also protect against mobility declines among older drivers. Scientifically proven cognitive training regimens have the potential to enhance the everyday lives of older adults. PMID:19491362

Changes in free amino acid content during naupliar development of the Calanoid copepod Acartia tonsa.

PubMed

Rayner, Thomas Allan; Jørgensen, Niels Ole Gerslev; Drillet, Guillaume; Hansen, Benni Winding

2017-08-01

Changes in free amino acids (FAA) were investigated in the potentially important live feed and neritic copepod species Acartia tonsa during naupliar development. Total content of FAA in A. tonsa nauplii was around 17% of dry weight at first development stage, and declined to 6% for later stages. Relative to body-volume and biomass, the FAA content indicated possible volume-dependent changes. However, changes in FAA with osmolytic activity could not account for this decline in FAA content, but suggests that the decline reflected degradation of residual FAAs from the embryonic stage. Glutamic acid revealed the largest change in relative abundance during naupliar development and declined from 29.0% at first nauplius stage to 7.1% at later stages. The high FAA pool in early naupliar stages may be necessary for naupliar development due to an absence of feeding at first development stages. The high FAA content in early nauplii indicates that A. tonsa is a valuable source for nutritional energy for first-feeding fish larvae and should be further exploited for aquaculture purposes. Enhancements to FAA abundances in nauplii through manipulation of maternal diets could be of future interest, as copepod nauplii can contain a substantial pool of FAAs at first development stage. Copyright © 2017. Published by Elsevier Inc.

Physical Activity and Change in Mammographic Density

PubMed Central

Conroy, Shannon M.; Butler, Lesley M.; Harvey, Danielle; Gold, Ellen B.; Sternfeld, Barbara; Oestreicher, Nina; Greendale, Gail A.; Habel, Laurel A.

2010-01-01

One potential mechanism by which physical activity may protect against breast cancer is by decreasing mammographic density. Percent mammographic density, the proportion of dense breast tissue area to total breast area, declines with age and is a strong risk factor for breast cancer. The authors hypothesized that women who were more physically active would have a greater decline in percent mammographic density with age, compared with less physically active women. The authors tested this hypothesis using longitudinal data (1996–2004) from 722 participants in the Study of Women's Health Across the Nation (SWAN), a multiethnic cohort of women who were pre- and early perimenopausal at baseline, with multivariable, repeated-measures linear regression analyses. During an average of 5.6 years, the mean annual decline in percent mammographic density was 1.1% (standard deviation = 0.1). A 1-unit increase in total physical activity score was associated with a weaker annual decline in percent mammographic density by 0.09% (standard error = 0.03; P = 0.01). Physical activity was inversely associated with the change in nondense breast area (P < 0.01) and not associated with the change in dense breast area (P = 0.17). Study results do not support the hypothesis that physical activity reduces breast cancer through a mechanism that includes reduced mammographic density. PMID:20354074

Loss of motor unit size and quadriceps strength over 10 years in post-polio syndrome.

PubMed

Bickerstaffe, A; van Dijk, J P; Beelen, A; Zwarts, M J; Nollet, F

2014-06-01

To investigate whether strength decline in post-polio syndrome (PPS) results from excessive distal axonal degeneration of enlarged motor units. We assessed changes over 10 years in isometric quadriceps strength, mean motor unit action potential (MUAP) size, root mean squared (RMS) amplitude, and level of interference (LOI) in 47 patients with PPS and 12 healthy controls, using high density surface EMG. At baseline, all patients had symptomatic quadriceps dysfunction, evidenced by transmission defects on single-fibre EMG. MU size and strength declined significantly by 20% and 15%, respectively in patients with PPS. Those with the largest initial MU sizes exhibited the greatest losses of mean MU size (27%) and proportional decreases in quadriceps strength (23%). Initial strength, change in LOI and change in RMS amplitude together explained 35% of the variability in strength changes in patients. MU size of controls did not change, although they lost 29% strength. MU size and strength declined concomitantly in a homogeneous cohort of patients with PPS and quadriceps dysfunction. This long term follow-up study provides evidence that size diminution of enlarged MUs combined with a reduced number of active MUs contributes to the gradual strength decline in PPS. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Survey of bumble bee (Bombus) pathogens and parasites in Illinois and selected areas of northern California and southern Oregon.

PubMed

Kissinger, Christina N; Cameron, Sydney A; Thorp, Robbin W; White, Brendan; Solter, Leellen F

2011-07-01

Pathogens have been implicated as potential factors in the recent decline of some North American bumble bee (Bombus) species, but little information has been reported about the natural enemy complex of bumble bees in the United States. We targeted bumble bee populations in a state-wide survey in Illinois and several sites in California and Oregon where declines have been reported to determine presence and prevalence of natural enemies. Based on our observations, most parasites and pathogens appear to be widespread generalists among bumble bee species, but susceptibility to some natural enemies appeared to vary. Copyright © 2011 Elsevier Inc. All rights reserved.

Why We Need Evidence-Based, Community-Wide Approaches for Prevention of Teen Pregnancy.

PubMed

Barfield, Wanda D; Warner, Lee; Kappeler, Evelyn

2017-03-01

Teen pregnancy and childbearing have declined over the past two decades to historic lows. The most recent declines have occurred during a time of coordinated national efforts focused on teen pregnancy. This article highlights a federal partnership to reduce teen pregnancy through the implementation of innovative, evidence-based approaches in affected communities, with a focus on reaching African-American and Latino/Hispanic youth. This initiative has the potential to transform the design and implementation of future teen pregnancy prevention efforts and provide a model that can be replicated in communities across the nation. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Excess longitudinal decline in lung function in grain farmers.

PubMed

Senthilselvan, Ambikaipakan; Chénard, Liliane; Grover, Vaneeta; Kirychuk, Shelley P; Hagel, Louise; Ulmer, Kendra; Hurst, Thomas S; Dosman, James A

2010-04-01

Workers in intensive agricultural operations are exposed to dust and endotoxin that are associated with respiratory effects. The authors investigated the longitudinal changes in lung function in male grain farmers. In this study, male grain farmers (n = 263) and male nonfarming control subjects (n = 261) studies initially in 1990/91 were followed-up in 1994/95 and 2003/04. After controlling for potential confounders, grain farmers had an excess annual decline of 9.2 ml/year (95% confidence interval [CI]: 2.7, 15.8, p = .006) in forced vital capacity (FVC) in comparison to control. Long-term exposure to grain dust and other substances in lifetime grain farmers results in progressive loss in lung function.

Dietary supplementation with coffee improves motor and cognitive performance in aged rats

USDA-ARS?s Scientific Manuscript database

Polyphenols found in fruits and nuts have anti-inflammatory properties that may provide protection against the decline of cognitive, motor and neuronal function in senescence. The presence of a number of bioactive compounds (e.g., polyphenols) implicates coffee as a potential nutritional therapeutic...

Automobile fuel economy : potential effects of increasing the corporate average fuel economy standards

DOT National Transportation Integrated Search

2000-08-01

Between 1981 and 1999, the average price of gasoline, adjusted for inflation, declined more than 60 percent. During the same period, the U.S. transportation sector's consumption of oil rose from less than 10 million to nearly 13 million barrels per d...

Coordinated Studies of Ultraviolet Radiation and Amphibians in Lentic Wetland Habitats

EPA Science Inventory

Ultraviolet radiation (UVR) has been suggested as a potential cause of population declines and increases in malformations in amphibians. This study indicates that the present distributions of amphibians in four western U.S. National Parks are not related to UVR exposure, and sugg...

Creativity in the Later Years: Optimistic Prospects for Achievement.

ERIC Educational Resources Information Center

Simonton, Dean Keith

1990-01-01

Claims that, despite apparent decline in productivity in final years of life, seven considerations suggest a far more favorable outlook: role of extrinsic influences; contingency on career age; impact of individual differences in creative potential; interdisciplinary variation in age curves; absence of age decrement on…

Analytical Versus Numerical Estimates of Water-Level Declines Caused by Pumping, and a Case Study of the Iao Aquifer, Maui, Hawaii

USGS Publications Warehouse

Oki, Delwyn S.; Meyer, William

2001-01-01

Comparisons were made between model-calculated water levels from a one-dimensional analytical model referred to as RAM (Robust Analytical Model) and those from numerical ground-water flow models using a sharp-interface model code. RAM incorporates the horizontal-flow assumption and the Ghyben-Herzberg relation to represent flow in a one-dimensional unconfined aquifer that contains a body of freshwater floating on denser saltwater. RAM does not account for the presence of a low-permeability coastal confining unit (caprock), which impedes the discharge of fresh ground water from the aquifer to the ocean, nor for the spatial distribution of ground-water withdrawals from wells, which is significant because water-level declines are greatest in the vicinity of withdrawal wells. Numerical ground-water flow models can readily account for discharge through a coastal confining unit and for the spatial distribution of ground-water withdrawals from wells. For a given aquifer hydraulic-conductivity value, recharge rate, and withdrawal rate, model-calculated steady-state water-level declines from RAM can be significantly less than those from numerical ground-water flow models. The differences between model-calculated water-level declines from RAM and those from numerical models are partly dependent on the hydraulic properties of the aquifer system and the spatial distribution of ground-water withdrawals from wells. RAM invariably predicts the greatest water-level declines at the inland extent of the aquifer where the freshwater body is thickest and the potential for saltwater intrusion is lowest. For cases in which a low-permeability confining unit overlies the aquifer near the coast, however, water-level declines calculated from numerical models may exceed those from RAM even at the inland extent of the aquifer. Since 1990, RAM has been used by the State of Hawaii Commission on Water Resource Management for establishing sustainable-yield values for the State?s aquifers. Data from the Iao aquifer, which lies on the northeastern flank of the West Maui Volcano and which is confined near the coast by caprock, are now available to evaluate the predictive capability of RAM for this system. In 1995 and 1996, withdrawal from the Iao aquifer reached the 20 million gallon per day sustainable-yield value derived using RAM. However, even before 1996, water levels in the aquifer had declined significantly below those predicted by RAM, and continued to decline in 1997. To halt the decline of water levels and to preclude the intrusion of salt-water into the four major well fields in the aquifer, it was necessary to reduce withdrawal from the aquifer system below the sustainable-yield value derived using RAM. In the Iao aquifer, the decline of measured water levels below those predicted by RAM is consistent with the results of the numerical model analysis. Relative to model-calculated water-level declines from numerical ground-water flow models, (1) RAM underestimates water-level declines in areas where a low-permeability confining unit exists, and (2) RAM underestimates water-level declines in the vicinity of withdrawal wells.

Potassium improves photosynthetic tolerance to and recovery from episodic drought stress in functional leaves of cotton (Gossypium hirsutum L.).

PubMed

Zahoor, Rizwan; Zhao, Wenqing; Dong, Haoran; Snider, John L; Abid, Muhammad; Iqbal, Babar; Zhou, Zhiguo

2017-10-01

To investigate whether potassium (K) application enhances the potential of cotton (Gossypium hirsutum L.) plants to maintain physiological functions during drought and recovery, low K-sensitive (Siza 3) and -tolerant (Simian 3) cotton cultivars were exposed to three K rates (0, 150, and 300 K 2 O kg ha -1 ) and either well-watered conditions or severe drought stress followed by a recovery period. Under drought stress, cotton plants showed a substantial decline in leaf water potential, stomatal conductance, photosynthetic rate, and the maximum and actual quantum yield of PSII, resulting in greater non-photochemical quenching and lipid peroxidation as compared to well-watered plants. However, plants under K application not only showed less of a decline in these traits but also displayed greater potential to recover after rewatering as compared to the plants without K application. Plants receiving K application showed lower lipid peroxidation, higher antioxidant enzyme activities, and increased proline accumulation as compared to plants without K application. Significant relationships between rates of photosynthetic recovery and K application were observed. The cultivar Siza 3 exhibited a more positive response to K application than Simian 3. The results suggest that K application enhances the cotton plant's potential to maintain functionality under drought and facilitates recovery after rewatering. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Bighorn sheep (Ovis canadensis) survivorship and habitat studies in Bighorn Canyon National Recreation Area and surrounding lands, Wyoming and Montana, 2000–2003

USGS Publications Warehouse

Schoenecker, Kathryn A.; Singer, Francis J.; Grams, Kayla A.; Roelle, James E.

2004-01-01

In the 1850s, bighorn sheep (Ovis canadensis) were numerous and distributed throughout the Bighorn and Pryor Mountains of Montana and Wyoming. After European settlement, bighorn sheep populations declined, and local extinctions occurred in much of their historic range in the western United States. The current bighorn sheep population of Bighorn Canyon National Recreation Area (BICA) is the product of several reintroductions into BICA and surrounding lands. Following a release in 1973 and growth rates near maximum potential of 19.8% per year, the population grew to an estimated peak population of about 211 animals in 1993 and 1994 (Kissell and others, 1996). Recent counts indicate the bighorn sheep population has declined. Kissell and others (1996) reported that the population began to decline rapidly in 1995 and 1996. He noted low ewe:lamb ratios during the decline phase. Bighorn sheep numbers declined to the lowest minimum viable population size of 100 animals recommended by several bighorn sheep experts (Bailey, 1990; Berger, 1990; Smith and others, 1991). National Park Service (NPS) and Bureau of Land Management (BLM) managers were concerned about the decline and requested a study of its causes. In 2000, the U.S. Geological Survey- Biological Resources Division (USGS-BRD) received funding to start a 3-year study of survivorship, condition, and population growth rate of the BICA bighorn sheep population.Several possibilities exist for the bighorn sheep decline. The herd may have experienced a rapid population expansion, followed by a decline to stability at a lower long-term carrying capacity. This pattern of apparently overshooting carrying capacity following an initial release has been reported for a number of ungulates (Caughley, 1976). Disease may have caused the decline; predation and/or competition with wild horses (Equus caballus) may also have been factors. A spatial model of wild horse carrying capacity (Coughenour, 1999) was developed to assist managers in evaluating wild horse population numbers. Studies of summer consumption rates by wild horses and other ungulates were conducted by James Detling and students from Colorado State University (Peterson and others, 1997; Gerhardt and Detling, 1998; Fahnestock, 1998). Diets and habitat use of wild horses, bighorn sheep and mule deer were studied by Coates and Schemnitz (1989) and Kissell and others (1996). Both Coates and Schemnitz (1989) and Kissell and others (1996) reported a high degree of dietary overlap between wild horses and bighorn sheep. However, Kissell and others (1996) concluded that a high degree of spatial separation between wild horses and bighorn sheep, at least under the study conditions, precluded any significant negative competitive influences. The most important overlap of bighorn sheep and wild horses seems to be on winter range. Competition can be difficult to determine, since current conditions may not reveal competition that has already occurred. Managers remained concerned about the declining bighorn population for the following reasons: Our objectives for the study were to: Evaluate current disease problems and mortality rates, including predation rates, in bighorn sheep through captures and monitoring of bighorn sheep.Determine winter spatial relations of wild horses and bighorn sheep through aerial surveys of winter range.Conduct habitat measurements to determine why bighorn sheep were not using what had been mapped with a GIS-based habitat model as suitable bighorn sheep habitat, and sample winter and summer consumption rates of key forage species to see if there were other factors precluding use of these areas by bighorn sheep.Compare winter lamb recruitment rates and total vegetation consumption rates on bighorn sheep winter use areas, with and without wild horses present.Complete year-round GIS-based distribution maps for wild horses and bighorn sheep in order to identify key areas of species overlap and key areas of species separation for potential habitat improvements.NPS park staff asked USGS to answer the following questions: (a) how large is the population?; (b) how many rams are in the population?; (c) in addition to low lamb recruitment, is mortality or dispersal of adults likely contributing to the decline?; and (d) is trophy hunting of rams contributing to the decline?

Apolipoprotein E ε2 and functional decline in amnestic mild cognitive impairment and Alzheimer disease.

PubMed

Bonner-Jackson, Aaron; Okonkwo, Ozioma; Tremont, Geoffrey

2012-07-01

Recent work has demonstrated the potentially protective effects of the apolipoprotein E (APOE) ε2 allele on cognitive functioning in individuals at risk for developing Alzheimer disease. However, little is known regarding the effect of ε2 genotype on rate of change in daily functioning over time. The aim of the current study was to examine the relationship between APOE genotype and change over time in ability to perform daily activities. We examined the relationship between APOE genotype and change in the ability to perform activities of daily living at 12- and 24-month intervals in 225 healthy comparison subjects, 381 individuals with amnestic mild cognitive impairment, and 189 individuals with Alzheimer disease who were enrolled in the Alzheimer's Disease Neuroimaging Initiative study. Neuropsychological measures were also collected at each follow-up. Overall, individuals with at least one APOE-ε2 allele showed less functional decline over time and better performance on neuropsychological measures than those without an ε2 allele, even after controlling for potential confounders. When diagnostic groups were examined individually, presence of the ε2 allele continued to be associated with slower functional decline, although the relationship was no longer statistically significant in most cases, likely due to reduced statistical power. Our findings suggest that the APOE-ε2 allele provides a buffer against significant changes in daily functioning over time and is associated with better neuropsychological performance across a number of measures.

Visually guided auditory attention in a dynamic "cocktail-party" speech perception task: ERP evidence for age-related differences.

PubMed

Getzmann, Stephan; Wascher, Edmund

2017-02-01

Speech understanding in the presence of concurring sound is a major challenge especially for older persons. In particular, conversational turn-takings usually result in switch costs, as indicated by declined speech perception after changes in the relevant target talker. Here, we investigated whether visual cues indicating the future position of a target talker may reduce the costs of switching in younger and older adults. We employed a speech perception task, in which sequences of short words were simultaneously presented by three talkers, and analysed behavioural measures and event-related potentials (ERPs). Informative cues resulted in increased performance after a spatial change in target talker compared to uninformative cues, not indicating the future target position. Especially the older participants benefited from knowing the future target position in advance, indicated by reduced response times after informative cues. The ERP analysis revealed an overall reduced N2, and a reduced P3b to changes in the target talker location in older participants, suggesting reduced inhibitory control and context updating. On the other hand, a pronounced frontal late positive complex (f-LPC) to the informative cues indicated increased allocation of attentional resources to changes in target talker in the older group, in line with the decline-compensation hypothesis. Thus, knowing where to listen has the potential to compensate for age-related decline in attentional switching in a highly variable cocktail-party environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer.

PubMed

Czernekova, Michaela; Jönsson, K Ingemar

2016-01-01

Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors.

Focused and divided attention in a simulated cocktail-party situation: ERP evidence from younger and older adults.

PubMed

Getzmann, Stephan; Golob, Edward J; Wascher, Edmund

2016-05-01

Speech perception under complex listening conditions usually decreases in aging. This is especially true for listening conditions requiring divided attention among 2 and more relevant speakers. Using a speech perception task and event-related potential measures, we studied the ability of younger and older adults to attend to speech information from a single-target speaker (focused attention) or from 2 different (alternative) target speakers (divided attention). The focused and divided attention conditions were presented either in silence or in the presence of 3 concurrent speakers. In the presence of concurrent speakers, older participants showed worse performance with divided versus focused attention. In contrast, there was no effect of attention condition for the younger adults. Relative to the young, event-related potential analysis in older subjects indicated a decline in preparatory activity for the critical speech information (a delayed and smaller contingent negative variation), and delayed attentional control (indicated by a longer P2 latency). Standardized low-resolution brain electromagnetic tomography revealed that the age-related decline in preparatory activity was associated with reduced activation of medial and superior frontal gyrus and anterior cingulate gyrus. The results suggest that age-related differences in these prefrontal brain areas reflect declines in preparatory attention and gating of subsequent task-related speech information, especially under conditions of divided attention. These findings may reflect mechanisms relating to impaired speech perception by older people in "cocktail-party" listening situations. Copyright © 2016 Elsevier Inc. All rights reserved.

Community and species-specific responses of wild bees to insect pest control programs applied to a pollinator-dependent crop.

PubMed

Tuell, Julianna K; Isaacs, Rufus

2010-06-01

Wild bee conservation is regarded as essential for sustainable production of pollinator-dependent crops, yet little is known about the effects on wild bee communities of typical insect pest management programs used postbloom. We developed an insecticide program risk (IPR) index to quantify the relative risk to wild bees of insecticide programs applied to blueberry fields. This was used to determine the relationship between IPR and the abundance, diversity, and richness of wild bee communities sampled during three successive flowering seasons. In 2 of 3 yr, bee abundance and species richness declined with increasing IPR. Bee diversity declined with IPR in one of 3 yr. These results indicate that wild bee communities are negatively affected by increasingly intensive chemical pest management activities in crop fields and that interyear variability in bee populations has the potential to mask such effects in short-term studies. When several wild bee species were analyzed separately, two of three solitary and one of three social blueberry-foraging species declined with increasing IPR values, suggesting that different life histories and nesting habits may help some bee populations escape the negative effects of insecticides applied after bloom. Pollinator conservation programs aimed strictly at reducing insecticide use may have varying success, depending on the biology of the target bee species. The IPR index provides a standard method to compare pest management programs for their potential effect on wild bee communities, with broad application for use in other agricultural systems.

River dolphins can act as population trend indicators in degraded freshwater systems.

PubMed

Turvey, Samuel T; Risley, Claire L; Barrett, Leigh A; Yujiang, Hao; Ding, Wang

2012-01-01

Conservation attention on charismatic large vertebrates such as dolphins is often supported by the suggestion that these species represent surrogates for wider biodiversity, or act as indicators of ecosystem health. However, their capacity to act as indicators of patterns or trends in regional biodiversity has rarely been tested. An extensive new dataset of >300 last-sighting records for the Yangtze River dolphin or baiji and two formerly economically important fishes, the Yangtze paddlefish and Reeves' shad, all of which are probably now extinct in the Yangtze, was collected during an interview survey of fishing communities across the middle-lower Yangtze drainage. Untransformed last-sighting date frequency distributions for these species show similar decline curves over time, and the linear gradients of transformed last-sighting date series are not significantly different from each other, demonstrating that these species experienced correlated population declines in both timing and rate of decline. Whereas species may be expected to respond differently at the population level even in highly degraded ecosystems, highly vulnerable (e.g. migratory) species can therefore display very similar responses to extrinsic threats, even if they represent otherwise very different taxonomic, biological and ecological groupings. Monitoring the status of river dolphins or other megafauna therefore has the potential to provide wider information on the status of other threatened components of sympatric freshwater biotas, and so represents a potentially important monitoring tool for conservation management. We also show that interview surveys can provide robust quantitative data on relative population dynamics of different species.

Fewer invited talks by women in evolutionary biology symposia

PubMed Central

Schroeder, J; Dugdale, H L; Radersma, R; Hinsch, M; Buehler, D M; Saul, J; Porter, L; Liker, A; De Cauwer, I; Johnson, P J; Santure, A W; Griffin, A S; Bolund, E; Ross, L; Webb, T J; Feulner, P G D; Winney, I; Szulkin, M; Komdeur, J; Versteegh, M A; Hemelrijk, C K; Svensson, E I; Edwards, H; Karlsson, M; West, S A; Barrett, E L B; Richardson, D S; van den Brink, V; Wimpenny, J H; Ellwood, S A; Rees, M; Matson, K D; Charmantier, A; dos Remedios, N; Schneider, N A; Teplitsky, C; Laurance, W F; Butlin, R K; Horrocks, N P C

2013-01-01

Lower visibility of female scientists, compared to male scientists, is a potential reason for the under-representation of women among senior academic ranks. Visibility in the scientific community stems partly from presenting research as an invited speaker at organized meetings. We analysed the sex ratio of presenters at the European Society for Evolutionary Biology (ESEB) Congress 2011, where all abstract submissions were accepted for presentation. Women were under-represented among invited speakers at symposia (15% women) compared to all presenters (46%), regular oral presenters (41%) and plenary speakers (25%). At the ESEB congresses in 2001–2011, 9–23% of invited speakers were women. This under-representation of women is partly attributable to a larger proportion of women, than men, declining invitations: in 2011, 50% of women declined an invitation to speak compared to 26% of men. We expect invited speakers to be scientists from top ranked institutions or authors of recent papers in high-impact journals. Considering all invited speakers (including declined invitations), 23% were women. This was lower than the baseline sex ratios of early-mid career stage scientists, but was similar to senior scientists and authors that have published in high-impact journals. High-quality science by women therefore has low exposure at international meetings, which will constrain Evolutionary Biology from reaching its full potential. We wish to highlight the wider implications of turning down invitations to speak, and encourage conference organizers to implement steps to increase acceptance rates of invited talks. PMID:23786459

Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer

PubMed Central

2016-01-01

Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors. PMID:27828978

Pre-exposure to drought increases the resistance of tropical forest soil bacterial communities to extended drought

PubMed Central

Bouskill, Nicholas J; Lim, Hsiao Chien; Borglin, Sharon; Salve, Rohit; Wood, Tana E; Silver, Whendee L; Brodie, Eoin L

2013-01-01

Global climate models project a decrease in the magnitude of precipitation in tropical regions. Changes in rainfall patterns have important implications for the moisture content and redox status of tropical soils, yet little is known about how these changes may affect microbial community structure. Specifically, does exposure to prior stress confer increased resistance to subsequent perturbation? Here we reduced the quantity of precipitation throughfall to tropical forest soils in the Luquillo Mountains, Puerto Rico. Treatments included newly established throughfall exclusion plots (de novo excluded), plots undergoing reduction for a second time (pre-excluded) and ambient control plots. Ten months of throughfall exclusion led to a small but statistically significant decline in soil water potential and bacterial populations clearly adapted to increased osmotic stress. Although the water potential decline was small and microbial biomass did not change, phylogenetic diversity in the de novo-excluded plots decreased by ∼40% compared with the control plots, yet pre-excluded plots showed no significant change. On the other hand, the relative abundances of bacterial taxa in both the de novo-excluded and pre-excluded plots changed significantly with throughfall exclusion compared with control plots. Changes in bacterial community structure could be explained by changes in soil pore water chemistry and suggested changes in soil redox. Soluble iron declined in treatment plots and was correlated with decreased soluble phosphorus concentrations, which may have significant implications for microbial productivity in these P-limited systems. PMID:23151641

Atlantic ocean surface waters buffer declining atmospheric concentrations of persistent organic pollutants.

PubMed

Nizzetto, Luca; Lohmann, Rainer; Gioia, Rosalinda; Dachs, Jordi; Jones, Kevin C

2010-09-15

Decreasing environmental concentrations of some persistent organic pollutants (POPs) have been observed at local or regional scales in continental areas after the implementation of international measures to curb primary emissions. A decline in primary atmospheric emissions can result in re-emissions of pollutants from the environmental capacitors (or secondary sources) such as soils and oceans. This may be part of the reason why concentrations of some POPs such as polychlorinated biphenyls (PCBs) have not declined significantly in the open oceanic areas, although re-emission of POPs from open ocean water has barely been documented. In contrast, results from this study show that several polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have undergone a marked decline (2-3 orders of magnitude for some homologues) over a major portion of the remote oligotrophic Atlantic Ocean. The decline appears to be faster than that observed over continental areas, implicating an important role of oceanic geochemical controls on levels and cycling of some POPs. For several lower chlorinated PCDD/Fs, we observed re-emission from surface water back to the atmosphere. An assessment of the effectiveness of the main sink processes highlights the role of degradation in surface waters as potentially key to explaining the different behavior between PCDD/Fs and PCBs and controlling their overall residence time in the ocean/atmosphere system. This study provides experimental evidence that the ocean has a buffering capacity - dependent on individual chemicals - which moderates the rate at which the system will respond to an underlying change in continental emissions.

Association of Long-Term Adherence to the MIND Diet with Cognitive Function and Cognitive Decline in American Women.

PubMed

Berendsen, A M; Kang, J H; Feskens, E J M; de Groot, C P G M; Grodstein, F; van de Rest, O

2018-01-01

There is increasing attention for dietary patterns as a potential strategy to prevent cognitive decline. We examined the association between adherence to a recently developed Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet with cognitive function and cognitive decline, taking into account the interaction between the apolipoprotein E ε4 genotype and the MIND diet. Population-based prospective cohort study. A total of 16,058 older women aged 70 and over from the Nurses' Health Study. Dietary intake was assessed five times between 1984 and 1998 with a 116-item Food Frequency Questionnaire. The MIND score includes ten brain-healthy foods and five unhealthy foods. Cognition was assessed four times by telephone from 1995 to 2001 (baseline) with the Telephone Interview for Cognitive Status (TICS) and by calculating composite scores of verbal memory and global cognition. Linear regression modelling and linear mixed modelling were used to examine the associations of adherence to the MIND diet with average cognitive function and cognitive change over six years, respectively. Greater long-term adherence to the MIND diet was associated with a better verbal memory score (multivariable-adjusted mean differences between extreme MIND quintiles=0.04 (95%CI 0.01-0.07), p-trend=0.006), but not with cognitive decline over 6 years in global cognition, verbal memory or TICS. Long-term adherence to the MIND diet was moderately associated with better verbal memory in later life. Future studies should address this association within populations at greater risk of cognitive decline.

Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change

PubMed Central

Wenger, Seth J.; Isaak, Daniel J.; Luce, Charles H.; Neville, Helen M.; Fausch, Kurt D.; Dunham, Jason B.; Dauwalter, Daniel C.; Young, Michael K.; Elsner, Marketa M.; Rieman, Bruce E.; Hamlet, Alan F.; Williams, Jack E.

2011-01-01

Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km2), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species’ physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations. PMID:21844354

Flow regime, temperature, and biotic interactions drive differential declines of trout species under climate change

USGS Publications Warehouse

Wenger, S.J.; Isaak, D.J.; Luce, C.H.; Neville, H.M.; Fausch, K.D.; Dunham, J.B.; Dauwalter, D.C.; Young, M.K.; Elsner, M.M.; Rieman, B.E.; Hamlet, A.F.; Williams, J.E.

2011-01-01

Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacting species of trout across the interior western United States (1.01 million km2), based on empirical statistical models built from fish surveys at 9,890 sites. Projections under the 2080s A1B emissions scenario forecast a mean 47% decline in total suitable habitat for all trout, a group of fishes of major socioeconomic and ecological significance. We project that native cutthroat trout Oncorhynchus clarkii, already excluded from much of its potential range by nonnative species, will lose a further 58% of habitat due to an increase in temperatures beyond the species' physiological optima and continued negative biotic interactions. Habitat for nonnative brook trout Salvelinus fontinalis and brown trout Salmo trutta is predicted to decline by 77% and 48%, respectively, driven by increases in temperature and winter flood frequency caused by warmer, rainier winters. Habitat for rainbow trout, Oncorhynchus mykiss, is projected to decline the least (35%) because negative temperature effects are partly offset by flow regime shifts that benefit the species. These results illustrate how drivers other than temperature influence species response to climate change. Despite some uncertainty, large declines in trout habitat are likely, but our findings point to opportunities for strategic targeting of mitigation efforts to appropriate stressors and locations.

Environment, behavior and physiology: do birds use barometric pressure to predict storms?

PubMed

Breuner, Creagh W; Sprague, Rachel S; Patterson, Stephen H; Woods, H Arthur

2013-06-01

Severe storms can pose a grave challenge to the temperature and energy homeostasis of small endothermic vertebrates. Storms are accompanied by lower temperatures and wind, increasing metabolic expenditure, and can inhibit foraging, thereby limiting energy intake. To avoid these potential problems, most endotherms have mechanisms for offsetting the energetic risks posed by storms. One possibility is to use cues to predict oncoming storms and to alter physiology and behavior in ways that make survival more likely. Barometric pressure declines predictably before inclement weather, and several lines of evidence indicate that animals alter behavior based on changes in ambient pressure. Here we examined the effects of declining barometric pressure on physiology and behavior in the white-crowned sparrow, Zonotrichia leucophrys. Using field data from a long-term study, we first evaluated the relationship between barometric pressure, storms and stress physiology in free-living white-crowned sparrows. We then manipulated barometric pressure experimentally in the laboratory and determined how it affects activity, food intake, metabolic rates and stress physiology. The field data showed declining barometric pressure in the 12-24 h preceding snowstorms, but we found no relationship between barometric pressure and stress physiology. The laboratory study showed that declining barometric pressure stimulated food intake, but had no effect on metabolic rate or stress physiology. These data suggest that white-crowned sparrows can sense and respond to declining barometric pressure, and we propose that such an ability may be common in wild vertebrates, especially small ones for whom individual storms can be life-threatening events.

The protective role of long-term meditation on the decline of the executive component of attention in aging: a preliminary cross-sectional study.

PubMed

Sperduti, Marco; Makowski, Dominique; Piolino, Pascale

2016-11-01

Life expectancy is constantly increasing. However, a longer life not always corresponds to a healthier life. Indeed, even normal aging is associated with a decline in different cognitive functions. It has been proposed that a central mechanism that could contribute to this widespread cognitive decline is an ineffective inhibitory attentional control. Meditation, to the other hand, has been associated, in young adults, to enhancement of several attentional processes. Nevertheless, attention is not a unitary construct. An influent model proposed the distinction of three subsystems: the alerting (the ability to reach and maintain a vigilance state), the orienting (the capacity of focusing attention on a subset of stimuli), and the conflict resolution or executive component (the ability to resolve conflict or allocate limited resources between competing stimuli). Here, we investigated, employing the Attentional Network Task (ANT), the specific impact of age on these three subcomponents, and the protective role of long-term meditation testing a group of older adults naïve to meditation, a group of age-matched adults with long-term practice of meditation, and a group of young adults with no previous meditation experience. We reported a specific decline of the efficiency of the executive component in elderly that was not observed in age-matched meditators. Our results are encouraging for the investigation of the potential beneficial impact of meditation on other cognitive processes that decline in aging such as memory. Moreover, they could inform geriatric healthcare prevention and intervention strategies, proposing a new approach for cognitive remediation in elderly populations.

Airport geomagnetic surveys in the United States

USGS Publications Warehouse

Berarducci, A.

2006-01-01

The Federal Aviation Administration (FAA) and the United States military have requirements for design, location, and construction of compass calibration pads (compass roses), these having been developed through collaboration with US Geological Survey (USGS) personnel. These requirements are detailed in the FAA Advisory Circular AC 150/5300-13, Appendix 4, and in various military documents, such as Handbook 1021/1, but the major requirement is that the range of declination measured within 75 meters of the center of a compass rose be less than or equal to 30 minutes of arc. The USGS Geomagnetism Group has developed specific methods for conducting a magnetic survey so that existing compass roses can be judged in terms of the needed standards and also that new sites can be evaluated for their suitability as potentially new compass roses. First, a preliminary survey is performed with a total-field magnetometer, with differences over the site area of less than 75nT being sufficient to warrant additional, more detailed surveying. Next, a number of survey points are established over the compass rose area and nearby, where declination is to be measured with an instrument capable of measuring declination to within 1 minute of arc, such as a Gurley transit magnetometer, DI Flux theodolite magnetometer, or Wild T-0. The data are corrected for diurnal and irregular effects of the magnetic field and declination is determined for each survey point, as well as declination range and average of the entire compass rose site. Altogether, a typical survey takes about four days to complete. ?? 2006 Springer.

Possible environmental factors underlying amphibian decline in eastern Puerto Rico: Analysis of U.S. government data archives

USGS Publications Warehouse

Stallard, R.F.

2001-01-01

The past three decades have seen major declines in populations of several species of amphibians at high elevations in eastern Puerto Rico, a region unique in the humid tropics because of the degree of environmental monitoring that has taken place through the efforts of U.S. government agencies. I examined changes in environmental conditions by examining time-series data sets that extend back at least into the 1980s, a period when frog populations were declining. The data include forest cover; annual mean, minimum, and maximum daily temperature; annual rainfall; rain and stream chemistry; and atmospheric-dust transport. I examined satellite imagery and air-chemistry samples from a single National Aeronautics and Space Administration aircraft flight across the Caribbean showing patches of pollutants, described as thin sheets or lenses, in the lower troposphere. The main source of these pollutants appeared to be fires from land clearing and deforestation, primarily in Africa. Some pollutant concentrations were high and, in the case of ozone, approached health limits set for urban air. Urban pollution impinging on Puerto Rico, dust generation from Africa (potential soil pathogens), and tropical forest burning (gaseous pollutants) have all increased during the last three decades, overlapping the timing of amphibian declines in eastern Puerto Rico. None of the data sets pointed directly to changes so extreme that they might be considered a direct lethal cause of amphibian declines in Puerto Rico. More experimental research is required to link any of these environmental factors to this problem.

CHALLENGES TO SUSTAINING DIADROMOUS FISHES THROUGH 2100: LESSONS LEARNED FROM WESTERN NORTH AMERICA

EPA Science Inventory

An evaluation of the history of efforts to reverse the long-term decline of Pacific Salmon in western North America provides instructive policy lessons for the potential recovery of diadromous fishes throughout the world. From California to southern British Columbia, wild runs of...

Building a Research Administration Infrastructure at the Department Level

ERIC Educational Resources Information Center

Chun, Maria B. J.

2010-01-01

Due to the current economic crisis, research administrators at public universities are grappling with declining state funding and are faced with identifying other potential sources of revenue to support operations. Research administrators at all levels are forced to do more with less. Department level research administrators must be innovative…

The role of genetics in chronic wasting disease of North American cervids

USDA-ARS?s Scientific Manuscript database

Chronic wasting disease (CWD) is an important management issue for many North American cervid populations. This fatal prion disease has led to deer population declines in areas with high infection rates and to economic loses even in low-prevalence areas. Because potential for cross-species transmiss...

Barred owl occupancy surveys within the range of the northern spotted owl

Treesearch

J. David Wiens; Robert G. Anthony; Eric D. Forsman

2011-01-01

The range expansion by barred owls (Strix varia) into western North America has raised considerable concern regarding their potential effects on declining northern spotted owl (Strix occidentalis caurina) populations, yet most information on the occurrence of barred owls in the region is limited to incidental detections during...

Crop rotation and residue management effects on deficit irrigated cotton and corn

USDA-ARS?s Scientific Manuscript database

Compared with disk tillage (DT), no-tillage (NT) retains residue and increases precipitation capture, which has the potential to reduce irrigation withdrawals from the declining Ogallala Aquifer. Our objective was to quantify DT and NT effects on water conservation during fallow and the subsequent y...

Development of sinkholes resulting from man's activities in the Eastern United States

USGS Publications Warehouse

Newton, John G.

1987-01-01

Alternatives that allow avoiding or minimizing sinkhole hazards are most numerous when a problem or potential problem is recognized during site evaluation. The number of alternatives declines after the beginning of site development. Where sinkhole development is predictable, zoning of land use can minimize hazards.

Potential Synergy: Rural School Districts and International Student Programs

ERIC Educational Resources Information Center

Casto, Hope G.; Steinhauer, Alexandra; Pollock, Pamela M.

2012-01-01

Many rural school districts face declining enrollments. A few districts have taken the unusual path of recruiting international students in order to boost their enrollments. This study examines a community using this strategy and the resulting financial, academic, and social situations for the school, community, and students, both local and…

Evaluating potential phosphorus management impacts in the Lake Eucha Basin using SWAT

USDA-ARS?s Scientific Manuscript database

Lake Eucha is a nexus of water quality conflicts between agribusiness and environmentalists, urban and rural stakeholders, municipalities and state governments. Lake Eucha is a drinking water supply reservoir for the City of Tulsa, declining water quality has been attributed to both municipal wastew...

CHALLENGES TO SUSTAINING DIADROMOUS FISHES THROUGH 2100: LESSONS LEARNED FROM WESTERN NORTH AMERICA

EPA Science Inventory

An evaluation of the history of efforts to reverse the long-term decline of Pacific salmon in western North America provides instructive policy lessons for the potential recovery of diadromous fishes throughout the world. From California to southern British Columbia, wild runs o...

Planting geometry and growing season effects on the growth and yield of dryland cotton

USDA-ARS?s Scientific Manuscript database

The declining Ogallala Aquifer beneath the Southern High Plains may necessitate dryland crop production and cotton (Gossypium hirsutum L.) is a well-adapted and potentially profitable alternative crop. The limited growing season duration of the Texas Panhandle and southwestern Kansas, however, impos...

A Rationale for Early Training in Music.

ERIC Educational Resources Information Center

Simons, Gene M.

1979-01-01

The ability of young children to learn music is commonly underestimated. There is a large amount of research and empirical evidence which indicates that (1) early childhood is the most critical period for learning fundamental concepts and skills in music and (2) children's potential for musical growth declines with age. (Author/NQ)

Thriving through Recession: Higher Education in a down Economy

ERIC Educational Resources Information Center

Goodman, Roger

2009-01-01

The constant flow of alarming economic and business news, rapidly declining endowments and potential disruption to the student-loan industry have all beaten down optimism about higher education's financial and strategic outlook. Universities large and small have announced budget cuts, layoffs, salary freezes, capital spending slowdowns and other…

Black Men in the Medical Education Pipeline: Past, Present, and Future.

ERIC Educational Resources Information Center

Ready, Timothy; Nickens, Herbert W.

1991-01-01

Factors in the decline in Black male enrollment in medical schools are examined, including the general medical school applicant pool, popularity of undergraduate biology degrees, Black enrollment in college, poverty, and employment opportunities. Social implications, areas for further research, and potential solutions are discussed. (Author/MSE)

Evaluation of potential alternative European pear cultivars for U.S. West Coast growers

USDA-ARS?s Scientific Manuscript database

California, Oregon, and Washington produced 98% of the commercial U.S. pear crop from 2003 to 2005, consisting of 'Williams Bartlett' (51%), 'Beurre Anjou' (36%), 'Beurre Bosc' (11%), and 2% others, mainly 'Doyenne du Comice', 'Red Clapp's Favorite', 'Seckel', and 'Concorde'. Declining processing d...

Planning Responses to Demographic Change. AIR 1986 Annual Forum Paper.

ERIC Educational Resources Information Center

Taylor, Bryan J. R.; Taylor, Elizabeth A.

A method for forecasting the number of college graduates in the United Kingdom is described, and suggestions are offered about ways that society should react to influence declining enrollments and potential reductions in technologically skilled graduates. Consideration is given to the implications of recruiting noncollege-bound individuals to…

Kenaf and cowpea as sugarcane cover crops

USDA-ARS?s Scientific Manuscript database

The use of cover crops during the fallow period prior to planting sugarcane has the potential to influence not only the following sugarcane crop, but the economics of the production system as a whole. Typically, a Louisiana sugarcane field is replanted every four years due to declining yields, and,...

Beyond Need and Merit: Strengthening State Grant Programs

ERIC Educational Resources Information Center

Jacobs, Christine, Ed.; Whitfield, Sarah, Ed.

2012-01-01

Recent increases in tuition levels, accelerated by declining state funding to institutions, have combined with stagnant or falling household incomes to make it more difficult for many college students to finance postsecondary education. In this environment, state grant programs are more important than ever. These funds have the potential to make…

Morphological correlates of hearing loss after cochlear implantation and electro-acoustic stimulation in a hearing-impaired Guinea pig model.

PubMed

Reiss, Lina A J; Stark, Gemaine; Nguyen-Huynh, Anh T; Spear, Kayce A; Zhang, Hongzheng; Tanaka, Chiemi; Li, Hongzhe

2015-09-01

Hybrid or electro-acoustic stimulation (EAS) cochlear implants (CIs) are designed to provide high-frequency electric hearing together with residual low-frequency acoustic hearing. However, 30-50% of EAS CI recipients lose residual hearing after implantation. The objective of this study was to determine the mechanisms of EAS-induced hearing loss in an animal model with high-frequency hearing loss. Guinea pigs were exposed to 24 h of noise (12-24 kHz at 116 dB) to induce a high-frequency hearing loss. After recovery, two groups of animals were implanted (n = 6 per group), with one group receiving chronic acoustic and electric stimulation for 10 weeks, and the other group receiving no stimulation during this time frame. A third group (n = 6) was not implanted, but received chronic acoustic stimulation. Auditory brainstem responses were recorded biweekly to monitor changes in hearing. The organ of Corti was immunolabeled with phalloidin, anti-CtBP2, and anti-GluR2 to quantify hair cells, ribbons and post-synaptic receptors. The lateral wall was immunolabeled with phalloidin and lectin to quantify stria vascularis capillary diameters. Bimodal or trimodal diameter distributions were observed; the number and location of peaks were objectively determined using the Aikake Information Criterion and Expectation Maximization algorithm. Noise exposure led to immediate hearing loss at 16-32 kHz for all groups. Cochlear implantation led to additional hearing loss at 4-8 kHz; this hearing loss was negatively and positively correlated with minimum and maximum peaks of the bimodal or trimodal distributions of stria vascularis capillary diameters, respectively. After chronic stimulation, no significant group changes in thresholds were seen; however, elevated thresholds at 1 kHz in implanted, stimulated animals were significantly correlated with decreased presynaptic ribbon and postsynaptic receptor counts. Inner and outer hair cell counts did not differ between groups and were not correlated with threshold shifts at any frequency. As in the previous study in a normal-hearing model, stria vascularis capillary changes were associated with immediate hearing loss after implantation, while little to no hair cell loss was observed even in cochlear regions with threshold shifts as large as 40-50 dB. These findings again support a role of lateral wall blood flow changes, rather than hair cell loss, in hearing loss after surgical trauma, and implicate the endocochlear potential as a factor in implantation-induced hearing loss. Further, the analysis of the hair cell ribbons and post-synaptic receptors suggest that delayed hearing loss may be linked to synapse or peripheral nerve loss due to stimulation excitotoxicity or inflammation. Further research is needed to separate these potential mechanisms of delayed hearing loss. Copyright © 2015 Elsevier B.V. All rights reserved.