A PRINCIPAL MODE OF CIRCULATION COVARIATION BETWEEN THE NORTHERN AND SOUTHERN HEMISPHERES AND ITS ASSOCIATION WITH ENSO DURING BOREAL WINTER

By employing the singular value decomposition(SVD) analysis, we have investigated in the present paper the covariations between circulation changes in the Northern(NH) and Southern Hemispheres(SH) and their associations with ENSO by using the NCEP/NCAR reanalysis, the reconstructed monthly NOAA SST, and CMAP precipitation along with NOAA Climate Prediction Center(CPC) ENSO indices. A bi-hemispheric covariation mode(hereafter BHCM) is explored, which is well represented by the first mode of the SVD analysis of sea surface pressure anomaly(SLPA-SVD1). This SVD mode can explain 57.36% of the total covariance of SLPA. BHCM varies in time with a long-term trend and periodicities of 3—5 years. The long term trend revealed by SVD1 shows that the SLP increases in the equatorial central and eastern Pacific but decreases in the western Pacific and tropical Indian Ocean, which facilitates easterlies in the lower troposphere to be intensified and El Ni觡o events to occur with lower frequency. The spatial pattern of the BHCM looks roughly symmetric about the equator in the tropics, whereas it is characterized by zonal disturbances in the mid-latitude of NH and is highly associated with AAO in the mid-latitude of SH. On inter-annual time scales, the BHCM is highly correlated with ENSO. The atmosphere in both the NH and SH responds to sea surface temperature anomalies in the equatorial region, while the contemporaneous circulation changes in the NH and SH in turn affect the occurrence of El Ni觡o/La Ni觡a. In boreal winter, significant temperature and precipitation anomalies associated with the BHCM are found worldwide. Specifically, in the positive phase of the BHCM,temperature and precipitation are anomalously low in eastern China and some other regions of East Asia. These results are helpful for us to better understand interactions between circulations in the NH and SH and the dynamical mechanisms behind these interactions.

Single‑Layer ZnO Hollow Hemispheres Enable High‑Performance Self‑Powered Perovskite Photodetector for Optical Communication

The carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light.Herein,we introduced single-layer hollow ZnO hemisphere arrays(ZHAs)behaving light trapping effect as the electron transport layer in perovskite photodetectors(PDs).The singlelayer hollow ZHAs can not only reduce the reflection,but also widen the angle of the effective incident light and especially transfer the distribution of the optical field from the ZnO/FTO interface to the perovskite active layer confirmed by the 3D finitedifference time-domain simulation.These merits benefit for the generation,transport and separation of carriers,improving the light utilization efficiency.Finally,our optimized FTO/ZHA/CsPbBr3/carbon structure PDs showed high self-powered performance with a linear dynamic range of 120.3 dB,a detectivity of 4.2×10^(12) Jones,rise/fall time of 13/28μs and the f_(−3) dB of up to 28 kHz.Benefiting from the high device performance,the PD was demonstrated to the application in the directional transmission of encrypted files as the signal receiving port with super high accuracy.This work uniquely utilizes the features of high-performance self-powered perovskite PDs in optical communication,paving the path to wide applications of all-inorganic perovskite PDs.

Metabolite changes in the ipsilateral and contralateral cerebral hemispheres in rats with middle cerebral artery occlusion

Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions（such as the contralateral cerebral hemisphere）. The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9-and 24-hour groups and the sham group. ~1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis（shown by the increase in lactate）, a perturbation of choline metabolism（suggested by the increase in choline）, neuronal cell damage（shown by the decrease in N-acetyl aspartate） and neurotransmitter imbalance（evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate） in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a difference in the metabolite changes induced by ischemic injury in the contralateral and ipsilateral cerebral hemispheres. Our findings demonstrate the presence of characteristic changes in metabolites in the contralateral hemisphere and suggest that they are most likely caused by metabolic changes in the ischemic hemisphere.

Differential Spontaneous Photon Emissions from Cerebral Hemispheres of Fixed Human Brains: Asymmetric Coupling to Geomagnetic Activity and Potentials for Examining Post-Mortem Intrinsic Photon Information

The emissions of biophotons have been considered a ubiquitous property of living systems and their components. We measured the “spontaneous” photon emissions from fixed whole and sectioned human brains within hyper-dark settings. Significant differences in photon counts were measured from different spatial planes. The flux densities were in the order of 2 × 10-12 W per m2. The right hemispheres but not the left hemispheres displayed more photon emissions whose spectral power density profiles exhibited a conspicuous amplitude peak between 7.9 and 8 Hz. Brains measured in the hyperdark (~10-12 W·m2) after removal from the typical lighting of the laboratory emitted more photons than those that had been maintained in the hyperdark for one week. The significant correlation between the numbers of photons emitted from the left hemisphere (but not the right) and global geomagnetic activity also exhibited energy equivalence between the photon flux densities and the geomagnetic shift within the cerebral volumes. These results indicate that what has been assumed to be fixed unresponsive human brain tissue still emits small numbers of photons that may be residuals from ambient light and can potentially interact with global geomagnetic activity. The medical implications for post-mortem intrinsic photonic information based upon the anisotropic microstructures within the hemispheres of the human cerebrum are discussed.

Unsteady Natural Convection between Two Eccentric Hemispheres

Natural convection heat transfer in open or closed cavities takes place in different engineering areas. The hemispherical cavity is a part of basic geometries although it is not widely studied. The present paper reports the numerical study of natural convection in a closed hemispherical annulus delimited by two vertically eccentric hemispheres filled with Newtonian fluid (air in this case with Pr = 0.7) is conducted. The inner hemisphere is heated by a heat flux of constant density and the outer one is maintained isothermal. Based on the Boussinesq assumptions, the governing equations are numerically studied using unsteady natural convection formulated with vorticity and stream-function variables. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The effect of the control parameters such as the Rayleigh number (103 ≤ Ra ≤ 106) or the eccentricity (e = ±0.2, ±0.5, 0) in the dynamic and thermal behaviours of the fluid is investigated.

Restoration of Ultimate Strength of Dented Hemispheres Under External Hydrostatic Pressure

This study aimed to restore the ultimate strength of dented stainless-steel hemispheres with a radius of 90 mm and a thickness of 0.86 mm.All of the hemispheres were subjected to external hydrostatic pressure.Small stainless-steel stiffened caps were used to eliminate the effect of indention on the ultimate strength.These caps had a radius of 36 mm,a thickness of 0.76 mm,and a height of 10.44 mm.Six hemispherical samples,including two intact hemispheres,two dented hemispheres without stiffening,and two dented hemispheres with stiffening,were prepared.Each hemi-sphere was geometrically measured for shape and thickness,hydrostatically tested for destruction,and numerically evaluated for comparison.The experimental and numerical data agreed well with each other.As a result,a spherical cap can effectively restore the ultimate strength of dented hemispheres under external hydrostatic pressure.The proposed restoration approach can be used to strengthen underwater pressure hulls with large local geometric imperfections.

Depth perception differences between hemispheres,genders,and eye dominance A study on evoked potential

BACKGROUND： Certain neural functions, such as peripheral reflexes, differ between genders, while higher brain functions, such as language, are asymmetrically distributed between the two hemispheres. The question remains as to whether depth perception differs between hemispheric laterality and genders, and whether it is affected by eye dominance. OBJECTIVE： To determine whether depth perception is influenced by factors such as gender, eye dominance, and hemispheric lateralization by recording evoked potential associated with depth perception. DESIGN, TIME AND SETTING： A contrast observation based on neuroelectrophysiology was performed at the Department of Biophysics of Ege University Medical School between June 2006 and April 2007. PARTICIPANTS： A total of 34 subjects, 19 females and 15 males, were included in the study with a mean age of （31.0 ± 6.9） years. All subjects were free of neurological or psychological disorders, or problems such as strabismus or vision correction. METHODS： Random-dot stereograms were used to elicit brain activity. A specially designed signal acquisition system employing two computers was used to record evoked potentials from both hemispheres via two pairs of scalp electrodes placed over the occipitotemporal areas of both hemispheres at symmetrical locations. MAIN OUTCOME MEASURES： Negative potential with a mean latency of （211.21 ±25.55） ms and a mean amplitude of （6.05 ± 1.53） pV was recorded from both occipitotemporal areas in 30 out of 34 participants. This was termed ＂Nd＂ and represented the evoked potential associated with depth perception. RESULTS： There were no significant differences in Nd amplitude or latency between the two hemispheres, the two eyes, or genders （P 〉 0.05）. CONCLUSION： The evoked potential associated with depth perception was not influenced by gender, hemisphere, or eye dominance.

Numerical Simulation of Natural Air Convection in Inclined Eccentric Hemispheres Enclosure

The subject of natural convection heat transfer is motivated by a wide range of applications in engineering technology. The hemispherical cavity is a part of basic geometries although it is not widely studied. The effect of inclinaison on natural convection fluid motions in the gap between two eccentric hemispheres is numerically studied. The inner hemisphere is subjected to a heat flux of a constant density and the outer one is maintened isothermal. The walls separating the two hemispheres are thermally adiabatic. Equations are formulated with vorticity and stream-functions variables. It is also assumed the fluid incompressible and obeys the approximation of Boussinesq. These equations are written by using bispherical coordinates system and solved by using a finite difference method. The results show the topology of flow is strongly dependent on the inclinaison because the flow can change from a unicellular regime to a multicellular regime by varying the inclination from 0 to π. By increasing the Rayleigh number (103<Ra<107), the flow intensifies. The results are shown in terms of streamlines and isotherms during their transient evolution.

LOW-FREQUENCY SUMMER MONSOON IN INDONESIA-NORTHERN AUSTRALIA AND ITS RELATION TO CIRCULATIONS IN BOTH HEMISPHERES

In terms of the expansion by extended empirical orthogonal function (EEOF) with data of ECMWF WMO and of outgoing longwave radiation(OLR) furnished by the NOAA polar-orbiting satellite,a study is made of November 1981 to March 1982 low-frequency (30--60 day)summer monsoon activity in the Indone- sian-North Australian zone (INAZ) together with its relation to atmospheric circulations in the Northern and Southern Hemispheres. Results show that at 850 hPa the southward blowing low-frequency NE(SW)wind from the eastern Asian coast changes, after crossing the euqator, to summer NW (SE) monsoon in the INAZ, which, when converging with (diverging from) the western-Australian enforced low-frequency SW (NE) wind, brings about strengthened (weakened) convection in the summer monsoon area and its eastward advance, with corresponding low- frequency variation shown in 850 hPa geopotential height. These outcomes are similar to those from the study of non-filtered actual observations, leading to the conclusion that the component of low-frequency variation illustrates major features characteristic of the variation in the tropical circulation.

ENSO-Independent Contemporaneous Variations of Anomalous Circulations in the Northern and Southern Hemispheres:The Polar-Tropical Seesaw Mode

Using the NCEP/NCAR reanalysis and the ENSO indices from the Climate Prediction Center over the period 1978-2014,we have investigated the contemporaneous circulation variations in the Northern and Southern Hemispheres by performing the singular value decomposition analysis of sea level pressure anomalies（SLPA） after the ENSO signal is regressed out.It is found that there exists a polar-tropical seesaw mode（PTSM） that characterizes with the out of phase fluctuations of SLPA between the polar and tropical regions in the Northern and Southern Hemispheres in boreal winter.This PTSM explains 47.74%of the total covariance of SLPA and is almost independent of ENSO.It demonstrates a long-term trend and oscillation cycles of 2-3 and 4-6 yr.The long-term trend in PTSM indicates that the sea level pressure gradually decreases in the tropics and increases in the polar region with time.This PTSM looks roughly symmetric about the equator besides the seesaw pattern of SLPA between the tropics and polar region in each hemisphere.The disturbances in the geopotential height field in association with the PTSM shows baroclinic features in the tropics whereas equivalent barotropic features in the mid and high latitudes in the troposphere.The anomalous thermal forcing in the tropical region is possibly one of the factors facilitating the formation of this PTSM.Significant global precipitation and temperature anomalies related to the PTSM are observed.In the positive PTSM phase,precipitation and temperature are higher than normal in southern Europe and the Mediterranean and surrounding areas,but lower than normal in northern Europe and Siberia.Precipitation is higher than normal while temperature is lower than normal in Northeast Asia.Significant temperature and precipitation anomalies possibly occur in the regions of western China,northern India,parts of North America,parts of subtropical Africa,Maritime Continent,and Antarctic.These results are helpful for better understanding of the circulation variations and the mechanisms behind the interactions between the Northern and Southern Hemispheres and the related winter climate anomalies over globe.

A Study on the Performances of Solar Air Collectors Having a Hemispherical Dimple on the Absorber Plate

In order to increase the efficiency of solar air collectors,a new variant with a protrusion is proposed in this study,and its performances are analyzed from two points of view,namely,in terms of optics and thermodynamics aspects.By comparing and analyzing the light paths of the protrusion and the dimple,it can be concluded that when sunlight shines on the dimple,it is reflected and absorbed multiple times,whereas for the sunlight shining on the protrusion,there is no secondary reflection or absorption of light.When the lighting area and the properties of the surfaces are the same,the absorption rate of the dimple is 10.3 percentage points higher than that of the protrusion.In the range of Reynolds number from 3000 to 11000,numerical simulations about the effects of the relative height(e/Dh=0.033–0.1)and relative spacing(p/e=4.5–8.5)of protrusions on air heat transfer and flow resistance show that,in terms of comprehensive evaluation coefficient(PF),the best relative height is 0.085,when the relative spacing is 5.A correlation of Nu and f with Re,e/Dh and p/e is obtained by linear regression of the results,in order to provide a useful reference for the design and optimization of this kind of solar air collector.

Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is<0 in the Northern Hemisphere;in the Southern Hemisphere when it is>0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere.

Study of the Effect of Acetic Acid and Phosphate on Copper Corrosion by Immersion Tests

It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L-1) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.

Motor rehabilitation of aphasic stroke patient:the possibility of Rood's approach

Aphasia is an acquired neurogenic language disorder that makes patients unable to comprehend or formulate language.Along with language impairment,patients suffering from aphasia face difficulties in reading,writing,and expressing themselves.The causes of aphasia are stroke,trauma,brain tumors,infections,and injury,particularly to the left hemisphere.About 20%of acute stroke cases in the world account for aphasia.Aphasia is categorized into:non-fluent and fluent forms.Non-fluent is further classified based on language and comprehension into:1)Broca’s aphasia,2)transcortical motor aphasia,3)global aphasia,and 4)transcortical mixed aphasia.

Development, and validation of non-speech dichotic listening test

Background:Classic dichotic listening tests using speech stimuli result in right ear advantage,due to the dominant crossed pathway for speech and language.It is presumed that similar crossed dominance could exist for non-speech stimuli too.Hence,this is an attempt to develop and validate the dichotic nonspeech test using environmental stimuli and explore the effect of focused attention on this test.Materials and method:Three lists of dichotic stimuli were created using these sounds with fifteen tokens in each list.Four professionals and non-professionals validated these materials.Normative estimation was obtained by administering the newly developed test on 70 adults and 70 children using a free-recall and forced-recall condition.Result:The results showed a significant difference between the left ear and right scores where the left ear score was better than the right,depicting left ear advantage(LEA)for free recall condition in both groups.In the forced recall condition,LEA was not seen;rather the mean score was significantly higher in the attended ear,irrespective of the stimuli presented to the right or left ear.The test-retest reliability in free recall was good in both the ears and moderate for forced right ear conditions.Conclusion:The novel test consistently showed LEA with good reliability and can be used to assess the hemispheric asymmetry in normal subjects and also in test batteries for the clinical population.

Geospatial characteristics of fire occurrences in southern hemispheric Africa and Madagascar during 2001-2020

For this study of long-term spatial patterns and trends of active fires in southern hemispheric Africa and on Madagascar from 2001 to 2020,active fire data from the MODIS FIRMS global fire data products were analyzed.The annual center of fire concentration tended to migrate toward the preserved rainforests and nature conservation areas in the Congo Basin and the mountain forests on the northeastern coast of Madagascar.Fire frequency varied seasonally at both study areas.We used geo statistical analysis techniques,such as measures of dispersion and emerging hot spot analysis,to reveal long-term trends in spatial patterns of fire events.In southern hemispheric Africa,the observed active fires tended to drift northward toward the Zambia-DRC border in the Congo basin.This northward migration progressed toward humid rainforests,which were better suited to sustaining repeated fire events.On Madagascar,the observed active fires tended to migrate toward the east coast in protected mountain forests.The spatial patterns of long-term trends showed a concentration of fires in the tropical regions of southern hemispheric Africa.Moreover,smaller clusters of new hot spots were located over eastern South Africa,overlapping with undifferentiated woodlands.On Madagascar,both hot and cold spots were identified and were separated by the highland region in the center of the island.Most of the eastern island was characterized by cold spots that received less precipitation than did the rest of the island.The presence of increasing hots spots in the densely vegetated areas highlights the urgent need for fire prevention and management in this region.

Role of Ocean Dynamics in the Seasonal Hadley Cell:A Response to Idealized Arctic Amplification

How atmospheric and oceanic circulations respond to Arctic warming at different timescales are revealed with idealized numerical simulations.Induced by local forcing and feedback,Arctic warming appears and leads to sea-ice melting.Deep-water formation is inhibited,which weakens the Atlantic Meridional Overturning Circulation(AMOC).The flow and temperature in the upper layer does not respond to the AMOC decrease immediately,especially at mid-low latitudes.Thus,nearly uniform surface warming in mid-low latitudes enhances(decreases)the strength(width)of the Hadley cell(HC).With the smaller northward heat carried by the weaker AMOC,the Norwegian Sea cools significantly.With strong warming in Northern Hemisphere high latitudes,the long-term response triggers the“temperature-wind-gyre-temperature”cycle,leading to colder midlatitudes,resulting in strong subsidence and Ferrel cell enhancement,which drives the HC southward.With weaker warming in the tropics and stronger warming at high latitudes,there is a stronger HC with decreased width.A much warmer Southern Hemisphere appears due to a weaker AMOC that also pushes the HC southward.Our idealized model results suggest that the HC strengthens under both warming conditions,as tropical warming determines the strength of the HC convection.Second,extreme Arctic warming led by artificially reduced surface albedo decreases the meridional temperature gradient between high and low latitudes,which contracts the HC.Third,a warmer mid-high latitude in the Northern(Southern)Hemisphere due to surface albedo feedback(weakened AMOC)in our experiments pushes the HC northward(southward).In most seasons,the HC exhibits the same trend as that described above.

Statistical Analysis on Gender Difference in Neural Activity for Spatial Ability Tasks

Gender differences are investigated from the viewpoint of cognitive neuroscience in the domain of spatial ability. Five task types of geometric problems are used for the collection of task-evoked fMRI data. Although there was no gender-difference in task performance, we found gender differences in neural activity. Some of the important gender differences that we found are 1) that there are far more joint neuro-activations among the brain regions, co-activations or reverse-activations, in males than in females, 2) that the two types of joint activations were nearly half and half in females while it was mostly co-activations in males, 3) that males tend to have more co-activations in the left hemisphere than expected while females tend to have more between-hemisphere co-activations than expected, and 4) that the left-right pairs of BA's are more highly associated than average for males while they are far less associated than average for females.

Largest Optical Time-domain Survey Telescope in Northern Hemisphere Goes into Operation

The new Wide Field Survey Telescope(WFST),located on the summit of Saishiteng Mountain,Lenghu Town,Qinghai Province of China,officially went into operation on September 17th,and released its first-light image-a portrait of the Andromeda galaxy,an object 2.5 million light years away from the Earth.Capable of surveying the whole northern sky in just three days,the 2.5-meter-aperture WFST now ranks the largest optical time-domain survey facility in the northern hemisphere.

Wernicke's encephalopathy in a rectal cancer patient with atypical radiological features:A case report

BACKGROUND Wernicke's encephalopathy is a disease caused by thiamine deficiency.The lesions usually involve the periphery of the aqueduct,midbrain,tectum,third ventricle,papillary body,and thalamus.It is very rare to affect the vermis and cerebellar hemispheres.CASE SUMMARY We report a 77-year-old female patient admitted to the emergency department of our hospital for 2 d of unconsciousness.Brain magnetic resonance imaging showed increased diffusion weighted imaging signals in the bilateral thalamus,periventricular regions of the third ventricle,corpora quadrigemina,vermis,and cerebellar hemispheres.Wernicke's encephalopathy was considered.She was given thiamine therapy and became conscious after the treatment.CONCLUSION Wernicke's encephalopathy may have various imaging manifestations.Clinicians should keep in mind that Wernicke’s encephalopathy may occur in patients who experience prolonged periods of malnutrition.